Search

• Effects of microstructure inhomogeneity on tensile deformation behavior of ZK60 Mg were clarified. • Tensile temperature and loading direction determined the slipping- or twinning-dominated deformation mode. • DRX was changed from continuous mode to discontinuous mode with increasing tensile temperature. • Welding zone showed superplastic behavior at tensile temperature > 300 °C due to the GBS effects. • The texture evolution was dependent on loading direction, tensile temperature and recrystallization mode. The tensile tests of the extruded ZK60 Mg containing a longitudinal weld seam were carried out at room and elevated temperatures, and the effects of induced microstructure inhomogeneity on tensile deformation behavior was clarified. The results show that the deformation mode, dynamic recrystallization (DRX), texture evolution and mechanical properties are strongly affected by the longitudinal weld seam, temperature, and loading direction. The room temperature (RT) deformation of welding zone is controlled by the dislocation slips with the association of some twins, while twinning plays significant roles in the accommodation of c -axis strain of the coarse grains on matrix zone. The deformation at RT stretched along extrusion direction (ED) and transverse direction (TD) are controlled by basal slip/twinning and basal slip/prismatic slip/twinning, respectively. During high temperature tension, the dislocation cross slip of pyramidal slip is activated, and grain boundary sliding occurred in welding zone, leading to the superplastic behavior. With the increase of tensile temperature, the predominant DRX mode is transformed from continuous DRX to discontinuous DRX. Moreover, the basal poles of the grains spread from TD towards ED with the decrease of maximum pole intensity when stretched along ED, while non-basal textures are transformed to 〈10–10〉 fiber texture when stretched along TD. The slip-dominated flow is seen during RT tension along ED, while twinning becomes predominant during RT tension along TD. The fine grain structure causes the superior RT tensile properties along ED of welding zone with ultimate tensile strength of 315 MPa and elongation to failure of 13.8%. With the increase of tensile temperature, the slipping-dominated deformation is transformed into twinning-dominated, causing the decrease of strength and increase of elongation. [ABSTRACT FROM AUTHOR]

Blending poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV) and poly(butylene adipate‐co‐ terephthalate) (PBAT) presents an effective approach to fabricate fully biodegradable polymer blends with tailored mechanical properties. This study investigated the composition on the mechanical properties and structure of PHBV/PBAT blend. The remarkable enhancement in elongation of the PHBV/PBAT blends was shown due to the ductile PBAT. The fracture behavior of the PHBV/PBAT specimens transited from brittle to ductile with the increase of the PBAT in the blends. Two different phases as a co‐continuous microstructure with a large interpenetrating structure indicate immiscibility between PHBV and PBAT in the PHBV/PBAT (50:50) specimen. The miscibility, intermolecular interaction, and mechanical properties of PHBV/PBAT blends were also investigated by molecular dynamics simulation. The results showed the immiscibility of PHBV and PBAT. The degradation temperature increased from 277 to 356°C with the increase of PBAT content in the PHBV/PBAT blend. Whereas the crystallinity ability of the PHBV component in the blend was confined by the PBAT phase, leading to a decrease in the overall crystallinity of PHBV. [ABSTRACT FROM AUTHOR]

In this study, extrusion experiments were carried out on Al-Mg-Si-Cu-Mn alloys with different extrusion ratios (ERs), extrusion temperatures (ETs), and extrusion speeds (ESs). By using electron backscatter diffraction (EBSD) analysis, tensile testing, and other analytical means, the evolution of microstructure, texture, and properties of the extruded alloys was systematically investigated, and the strengthening-toughening mechanism induced by the extrusion parameters was revealed. It was found that the strength of the extruded alloy shows a tendency to first increase and then decrease with the increase of the ER and ES, and the 'critical ER' and 'critical ES' are 29.5 and 2.5 mm/s, respectively; the strength of the extruded alloy gradually increases with the increase of the ET. The alloy achieved excellent strength-toughness matching at the ER of 29.5, ET of 480 °C, and ES of 2.5 mm/s. The yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) of the extruded alloy at this condition were ∼169.58 MPa, ∼314.36 MPa, and ∼16.57 %, respectively. This excellent strength-toughness matching is mainly related to the following aspects: 1) grain refinement provides high grain boundary strengthening effect and appropriate work hardening ability; 2) <111>//ED texture has a strong preferential orientation; 3) the variation trend of dislocation density is importantly related to <111>//ED and EX a {011}<111> textures; 4) Cube{001}<100> and Goss{011}<100> textures have a softening effect. The above findings provide new insights into the potential mechanisms of hot extrusion forming of aluminum alloys, which are of important guiding for the design and development of aluminum alloys with excellent strength-toughness combinations. [Display omitted] • <100>//ED texture is related to Cube{001}<100> and Goss{011}<100> textures. • Cube{001}<100> and Goss{011}<100> textures have a softening effect. • <111>//ED texture has a strong preferential orientation. • Dislocation density is importantly linked to <111>//ED and EX a {011}<111> textures. • Excellent strength-toughness matching of Al-Mg-Si-Cu-Mn extrusion alloys can be realized under specific extrusion parameters. [ABSTRACT FROM AUTHOR]

The fine-grained structures following deformation would be retained by using online quenching treatment which would achieve the purpose of simplifying formation process and reducing energy consumption. This study examined the effects of hot deformations on grain morphology, dynamic precipitation behavior and age-hardening response of the alloy after online quenching. And the dynamic precipitates re-solution behavior after online assisted heating were analyzed. The results indicated that the age-hardening response of the alloy was primarily controlled by the deformation temperature, and the appropriate deformation temperature range for online quenching was determined as 475–500 °C. Most of the deformed grains exhibited <110> Al //CD orientation. The increase in deformation temperature induced the transformation of the deformed grains from <110> Al //CD to <100> Al //CD orientation. A number of coarse second phases would be observed when the alloy was deformed below the optimal temperature range (e.g. 450 °C). For this case, it was suggested that the deformed alloy was heated by online assisted heating for a short time with the remaining heat after hot deformation, promoting most of the dynamic precipitates to be re-dissolved before online quenching. As a result, the deformation temperature window suitable for online quenching in 2195 Al–Li alloy could be broadened to 450–500 °C. • Deformation temperature range suitable for online quenching is 475–500 °C. • The grain morphology after online quenching retains fine-grained structure. • Deformation temperature is the primary factor in influencing the hardness. • Online assisted heating would efficient re-solution of the coarse phases. [ABSTRACT FROM AUTHOR]

The microstructure evolution of Mg-5.65Zn-0.66Zr (wt.%) alloy was studied based on the hot compression tests. The results indicated that the flow stress increased rapidly to a peak point at the initial stage, and then it gradually decreased. Moreover, high temperature and low strain rate resulted in the decreasing of flow stress. All samples exhibited a necklace grain structure because of the occurrence of partial dynamic recrystallization (DRX). High temperature increased both the size and fraction of DRXed grains, while high strain rate showed an opposite tendency. At the conditions of 350 °C/0.001 s−1 and 350 °C/0.1 s−1, the twins were not exhibited and DRX played a dominant role. Importantly, the obvious split of basal texture was observed. The pyramidal < c + a > slip with high value of Schmid factor was active in large deformed grains, which corresponded to the peak split point in (0001) pole figure. A mechanism about the grain rotation was proposed to explain the relationship between the pyramidal slip and the split of basal texture. Finally, it was found that large number of {10–12} extension twins were formed during the initial stage at condition of 300 °C/1 s−1, and the number of twins decreased with the increase of strain. The twins greatly contributed to the fast formation of basal texture and grain rotation. Moreover, the non-basal slips were active in twining region, which could facilitate the nucleation of DRX. [ABSTRACT FROM AUTHOR]

Al/Mg/Al sheet with good bonding quality and mechanical properties was fabricated based on the proposed porthole die co-extrusion and forging (PCE-F) process. There were no voids, cracks or other defects on the Al/Mg interface. A continuous diffusion zone with two-sub-layer structure was formed across the Al/Mg interface, and its width increased with higher temperature or reduction ratio. The sub-layers formed at low and high temperature were identified to be solid solutions and intermetallic compounds (IMCs) including γ-Mg 17 Al 12 and β-Al 3 Mg. In Al layer, the welding zone mainly consisted of fine equiaxed grains with several coarse elongated grains, while the majority of matrix zone is coarse elongated grains. The rolling textures were dominated in both welding and matrix zones. In Mg layer, the welding zone exhibited complete DRXed grain structure, while several unDRXed coarse grains were observed in the matrix zone. With the increasing temperature, the grain size of Al and Mg layer firstly decreased and then increased. High reduction ratio strongly refined the grain structure of Al layer, while slightly affected the Mg layer. The Al/Mg/Al sheet experienced stress-drops twice during the tensile test. The first stress-drop was determined by the IMCs and microstructure of Mg layer, while the second stress-drop was closely related to the microstructure of Al layer. Al/Mg/Al sheet forged at the lowest temperature without the formation IMCs exhibited the highest stress for the first stress-drop, and that forged under the highest reduction ratio with the smallest grain size in Al layer had the highest stress for the second stress-drop. [ABSTRACT FROM AUTHOR]

Thin-walled and hollow profiles of magnesium alloys have more light-weight advantages. However, longitudinal welds exist inevitably in hollow profiles produced by porthole die extrusion. The welding qualities of the welds have a critical impact on mechanical properties of the profiles. In this paper, hot extrusion experiments of an asymmetrical hollow magnesium alloy profile extruded at different ram speeds were carried out. The effects of extrusion speed on grain structure, second phase particles, texture and mechanical properties of longitudinal welds in hollow profiles were systematically studied. The effects of microstructure and texture on mechanical properties of longitudinal welds were revealed. The fracture morphology and fracture mode of the welds extruded at different ram speeds were analyzed. A method based on K criterion for evaluating the welding quality of magnesium alloy profile in three-dimensional space was proposed. The values of three-dimensional welding quality factor K 3D and non-dimensional welding quality factor K ⁎ of the hollow magnesium alloy profile were determined respectively. Finally, the welding qualities of longitudinal welds in the hollow magnesium alloy profiles extruded at different ram speeds were evaluated. Unlabelled Image • Microstructure and mechanical properties evolution at welding area were revealed. • The grain structure on the weld is finer than that of the reference area. • The extruded profile at welding area exhibits a split and tilted basal texture. • Higher extrusion speeds lead to better welding quality and mechanical properties. • The three-dimensional welding quality evaluation method shows high accuracy. [ABSTRACT FROM AUTHOR]

Abstract Aluminum alloy profiles manufactured by semi-continuous porthole die extrusion have three kinds of intrinsic features: longitudinal welds, transverse welds and back-end defects, which affect the corrosion resistance and mechanical properties of the profiles. In this work, the microstructure, corrosion resistance and mechanical properties of these intrinsic features were studied by microstructural characterization, chemical immersion and in-situ test, and the relationship between the material flow behavior and the evolution of the back-end defect and transverse weld was revealed through numerical simulation. It is found that, in terms of corrosion resistance and mechanical properties, both the transverse weld and back-end defect are poor, while the longitudinal weld is relatively good. Impurities and oxide particles are densely distributed in the aluminum alloy matrix in the back-end defect area. In the transverse weld area, the bonding interface has impurities and oxides, and grains are separated by the bonding interface; while in the longitudinal weld area, the grains across the bonding interfaces are formed. The bonding interface of the ring-shaped transverse weld which is far from the longitudinal weld has a low bonding degree. When the transverse weld becomes no longer ring-shaped and very close to the longitudinal weld, its bonding degree is greatly enhanced. The bonding degree of all the transverse welds is lower than that of all the longitudinal welds. During the tensile tests of the extruded profiles, strain concentration phenomena occur at the positions of the longitudinal welds, transverse welds and back-end defects, and there are two types of fracture modes: "uniform plastic deformation → strain concentration → fracture" and "uniform plastic deformation → strain concentration → debonding → fracture". [ABSTRACT FROM AUTHOR]

This paper systematically explored the effects of molecular structure on the foaming behavior of poly(ether-block-amide) (PEBA) and its influence on foam cyclic compression properties. It was demonstrated that increasing the hard segment (HS) content of PEBA not only improved crystallization and melting strength, but also narrowed the melting peak and shifted it to higher temperatures. In contrast to other thermoplastic elastomers such as TPU, PEBA with a higher HS content showed a lager foam expansion ratio but a narrower foaming window. Increasing HS content improved compression strength but deteriorated resilience of PEBA foams. As the expansion ratio increased to 5-fold, there was no significant reinforcing effect of HS on strength and modulus of PEBA foams, while the resilience of the foams increased constantly with decreasing HS content and increasing expansion ratio. [Display omitted] • Structure-tunable PEBA foams with various HS contents were prepared. • Melting peak of PEBA with more HS narrowed and shifted to higher temperatures. • Increasing HS content broadened foam expansion ratio but narrowed foaming window. • Reinforcement of HS on strength was limited as expansion ratio increased. • Resilience increased with decreasing HS content and increasing expansion ratio. [ABSTRACT FROM AUTHOR]

[Display omitted] • Constitutive relationship model and processing map of alloy were established. • The law of Z parameters on age-hardening response of alloy was researched. • The influence of Z parameters on quenching sensitivity of alloy was analyzed. • Quenching precipitation mechanism of alloy was revealed. • Second phases are different in the homogenized and hot-deformed samples. Al-Li alloys suffer from a narrow processing window. The hot deformation behavior of the ramp heating homogenized 2195 Al-Li alloy was investigated by hot compression test in the temperature range of 300–500 °C and strain rate range of 0.01–10 s−1, and the strain compensated Arrhenius constitutive relationship model and processing map of the alloy were established. The laws of Zener-Hollomon parameters on the age-hardening response and quenching sensitivity of the deformed alloy were analyzed. The quenching precipitation mechanism of the deformed alloy were revealed. The results showed that the hardness of the aged alloy tends to increase first and then decrease with increasing Z parameter, while the quenching sensitivity tends to decrease first and then increase. The quench-induced phases are precipitated under the induction of incoherent Al 3 Zr dispersoids within recrystallized grains. The boundary angle would affect the quenching precipitation behavior. It was also found that the types and amounts of second phases are significantly different between the homogenized and hot-deformed samples under slow cooling rate. The ramp heating homogenized 2195 Al-Li alloy after hot deformation at temperatures of 455–500 °C and strain rates below 1 s−1 possesses a lower flow stress, higher age-hardening response and smaller quenching sensitivity. [ABSTRACT FROM AUTHOR]

A large-scale billet of 2195 Al-Cu-Li alloy was prepared by spray deposition technology. The hot extrusion, solution treatment, pre-stretching, and aging treatment were performed on the deposited billet. It was found that the yield strength, ultimate tensile strength and elongation of the T83-treated alloy reach 600 MPa, 632 MPa and 10%, respectively. The microstructures of the deposited alloy in the thermo-mechanical processing were studied by optical microscopy, scanning electron microscopy and transmission electron microscopy. The mechanical properties were examined by tensile test. It was found that the spray deposited alloy presents a microstructure with fine equiaxed grains and low segregation degree. After hot extrusion, a typical fibrous structure with incomplete recrystallization is formed. After solution and aging treatments, lots of T 1 and δ ′ phases precipitate in the matrix, leading to significant increase of the tensile strength. Pre-stretch prior to aging treatment produces a fine homogeneous distribution of the T 1 plates throughout the matrix, which lead to an excellent tensile performance. The ductility of aged alloys is affected by the microstructure of grain boundary. Narrow precipitate free zone and dispersed grain boundary precipitates with small size are beneficial to improvement of alloy's ductility. [ABSTRACT FROM AUTHOR]

A new type of wrought magnesium alloy Mg-3.0Zn-1.0Sn-0.3Mn-0.3Ca (ZTMX3100) was developed in this work. The effects of extrusion temperature (200–400 °C) on grain structure, second phase particle, texture, and mechanical properties of the alloy were systematically investigated by combining microstructure observations and mechanical properties tests. The results indicated that dynamic recrystallization occurs at 200–400 °C in the alloy. As the extrusion temperature increases, the average grain size increases gradually from 2.6 μm to 17.8 μm due to different degrees of grain growth, the continuous CaMgSn phase bands are gradually broken into discontinuous chain-like or dot-like structures, and the grains and CaMgSn phases distribute more uniformly. The as-extruded alloys exhibit a typical extruding texture with (0001) basal planes parallel to the extrusion direction. The bar extruded at 300 °C presents the optimum comprehensive mechanical properties, which is attributed to the combined effect of relatively small grain size, uniformly distributed discontinuous particles, and weak basal texture. Finally, the quantitative relationship between grain size and Zener-Hollomon parameter and the quantitative relationship between the yield strength of the alloy and extrusion temperature were obtained. [ABSTRACT FROM AUTHOR]

Porthole die extrusion process of aluminum alloy profiles is a hot deformation process involving solid state welding. Microstructural evolution of welding seams is the key factor to determine mechanical properties of extruded profiles. In this work, the grain structure, bonding interface structure and precipitates of welding seams in the profiles extruded under different billet heating temperatures and extrusion speeds were characterized, and the hardness, strength and ductility of welding seams were analyzed. The influence of billet heating temperature and extrusion speed on the microstructure and mechanical properties of welding seams was studied. It was found that, in the porthole die extrusion process of aluminum alloy profiles, fine or coarse grains and micro-voids can be formed in welding seams. Although the new grains through the bonding interface have been formed, there are still many micro-voids in these new grains. Increasing billet heating temperature and extrusion speed not only contributes to the formation of the new grains through the bonding interface, but also promotes the closure of the micro-voids on the bonding interface, and thereby improves the atomic bonding degree of the material on both sides of the bonding interface. The hardness, strength and ductility of the extruded profiles can be improved by increasing billet heating temperature and extrusion speed. [ABSTRACT FROM AUTHOR]

In this study, the porthole die extrusion experiments were carried out to study the welding quality of longitudinal weld seams (L-seam) of high-strength 7075 aluminum alloy. The differences in microstructure and mechanical properties of L-seams under various extrusion temperatures and at different positions along extrusion direction were discussed. Moreover, three-dimensional transient numerical modeling was employed to have a better understanding on experimental findings. Based on the results, it was firstly proposed that the cross section of the profile can be divided into welding zone, transition zone, and matrix zone. Dynamic recrystallization completely occurred in the welding zone, while its fraction gradually decreased in transition and matrix zones, and this phenomenon was also verified by simulated results. The welding quality of L-seams near the front of the profile was relatively poor, while it was enhanced along the opposite direction of extrusion. Moreover, higher extrusion temperature was beneficial to enhance the welding quality of L-seams. Finally, the evolution of dynamic recrystallization and the evaluation of L-seam quality were analyzed based on simulated results and J criterion, all of which showed good agreement with the experimental findings. [ABSTRACT FROM AUTHOR]

The effects of billet heating temperature and extrusion speed on the microstructures and mechanical properties of longitudinal welds in the aluminum alloy profiles with complex cross-section were studied. The results show that as the billet heating temperature or extrusion speed gradually increases, the average grain size shows a decreasing trend, the average grain boundary misorientation angle shows an increasing trend, and the density of dislocations increases first and then decreases. The elongation (EL) shows a trend of increasing first and then decreasing. Higher billet heating temperature contributes to increase the ultimate tensile strength (UTS) and yield strength (YS) of the longitudinal welds, while extrusion speed has little effect. Poor welding quality is the main factor leading to the low mechanical properties of the longitudinal welds. When the welding quality is higher, the interaction between dislocations and precipitation phases has an important impact on the mechanical properties of the longitudinal welds. The longitudinal welds of the profiles studied in this work have the highest EL and the largest UTS when the combinations of the billet heating temperature and the extrusion speed are 490 °C × 3.5 mm/s and 520 °C × 3.5 mm/s, respectively. • The effects of extrusion parameters on longitudinal welds were clarified. • The effecting mechanisms of extrusion parameters on longitudinal welds were revealed. • Except welding quality, microstructures also seriously affect mechanical properties. [ABSTRACT FROM AUTHOR]

Compression tests of multi-crystalline tungsten with Gleeble 3800 thermal simulator were performed in the temperature range of 1250–1550 °C and strain rate range of 0.001–1 s − 1 . The flow stress-strain data of multi-crystalline tungsten were obtained. The processing map of the tungsten was established according to the theory of power dissipation and instability criterion. Together with the characterization of the microstructure, the flow instability domain and stability domain in hot deformation process of multi-crystalline tungsten were analyzed. The results of the tests and analysis showed that the dynamic recovery is the principal softening effect in the hot deformation process of multi-crystalline tungsten at elevated temperature. When the temperature reaches 1250 °C, a small amount of dynamic recrystallization occurs. It was found from the hot processing map that the stability deformation domain of multi-crystalline tungsten can be classified into four different situations in the strain range of 0.1–0.6. The temperature range and strain rate range corresponding to these four situations of stability deformation domain were given. [ABSTRACT FROM AUTHOR]

Solid-state bonding is an important problem in hot extrusion process of aluminum alloy profiles, especially for hollow section profiles. Predicting and decreasing the length of transverse weld seam (T-seam), improving the solid-state bonding degree and controlling microstructure of longitudinal weld seam (L-seam) are major concerns. In this work, a set of porthole extrusion dies with different shapes of legs (pointed and square) and depths of welding chambers were designed and manufactured. A series of extrusion experiments for different die structure parameters were performed, and microstructure observations, tensile tests and fracture feature analyses for the extruded profiles were conducted. The influences of the shapes of legs and the depths of welding chambers on the evolution and the length of T-seams and on the formation, microstructure and mechanical properties of L-seams were respectively investigated by means of experiment and numerical simulation. The distribution law of the ratio of pressure to material flow stress, p/σ , and the material flow behavior in welding plane were studied by using numerical simulation method. The results showed that the profiles extruded by the dies with pointed legs have single-convex T-seams and straight L-seams on their cross sections, and their T-seams are relatively shorter but their ductility is relatively inferior. While, the profiles extruded by the dies with square legs have double-convex T-seams and cross-shaped L-seams, their ductility is relatively superior but their T-seams are longer. With the increase of the depth of welding chamber, the ductility of the extruded profiles is increased, but the lengths of T-seams are almost invariable. In addition, it was found from numerical simulation results that, in the welding plane, the deforming material with a higher flow velocity has a lower value of p/σ , and vice versa. It was concluded that an effective welding zone should exist in the welding plane, and the deforming material only in this effective welding zone can flow into the extrusion die bearing to form an L-seam in extruded profile. [ABSTRACT FROM AUTHOR]

ABSTRACT This work studied the effects and action mechanism of high-temperature annealing process parameters, such as annealing temperature, annealing duration and cooling speed, on the microstructural evolution of polypropylene (PP) on different thickness layers, the surface quality, and mechanical properties of PP plastic parts. The results show that when the PP plastic parts are annealed at slightly higher than 100°C, the resin on the surface and internal layers of plastic parts just generates the relaxation and rearrangement at the molecular level. Only at an enough high annealing temperature, the secondary crystallization and phase transformation process can be observed. The crystallinity of all annealed samples is higher than that of unannealed samples, but the crystallinity is decreased with the increase of cooling speed after annealing duration, and the annealing duration exceeding 60 min almost has no effect on the crystallinity. The microstructural change of PP on the internal layer of plastic parts is weaker than that on the surface layer. The surface hardness of the plastic parts mainly depends on the crystallinity of the surface layer, whereas the surface roughness of the plastic parts depends on not only the crystallinity, but also the space conformation of molecular chains and the residual stress. With the change of annealing process parameters, the tensile and impact strengths of plastic parts show a non-monotonic change law. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42773. [ABSTRACT FROM AUTHOR]

To study the effects of extrusion parameters on the microstructure, texture, and mechanical property of 2195 Al–Li alloy, several extrusion experiments were carried out at different extrusion temperatures and speeds. A profile with different aspect ratios was designed, and the corresponding extrusion die was also designed and manufactured. The effects of aspect ratio, extrusion temperature, and speed on the microstructure and mechanical properties were investigated. The results show that cylindrical fiber grains and strong fiber textures of <111> and <100>//ED can be formed in the symmetrical areas with a low aspect ratio, which makes the profile at the areas have higher tensile strength along the extrusion direction and cause greater anisotropy of mechanical property. With the increase of aspect ratio, the grain structure turns into flat shape, and the fiber textures also change to {011}<211> and {011}<311>, the proportion of the {011}<311> texture component is higher at the area with a larger aspect ratio. This change in texture reduces the longitudinal strength of the profile and improves the transverse strength, which thus reduces the degree of anisotropy. As the extrusion temperature increases, the tensile strength of the profile can be increased due to the enhanced solution strengthening. However, excessive extrusion temperature will lead to obvious recrystallization and grain coarsening, which seriously reduces the formability and plasticity of the profile. Increasing the extrusion speed is beneficial to the dissolution of secondary particles into the matrix, which improves the strength of the profile. The grain size and recrystallization are little influenced by the extrusion speed. The increase of extrusion speed promotes the formation of the texture of {011}<311>, which improves the transverse strength of the profile and reduces the anisotropy. [Display omitted] • Fiber-like grains at large aspect position improve the elongation of profile. • The large aspect ratio enhances the {011}<311> texture and reduces the anisotropy. • The {011}<311> texture related to low anisotropy is also increased by high extrusion speed. • High extrusion temperature promote REX and Cube texture, which reduce the anisotropy. • Excessive temperature causes serious REX and grain growth and damages the ductility. [ABSTRACT FROM AUTHOR]

Al-Li alloys are considered as promising materials for the aircraft and aerospace industries. As an effective way of producing complex profiles, the hot extrusion process has become more attractive. Here, isothermal extrusion of homogenized 2196 Al-Li alloys under the temperature of 703–783 K and extrusion speed of 0.1–1.0 mm/s was implemented. The microstructure and mechanical properties of extruded profiles under different processing conditions were evaluated. The results showed that the homogenization could eliminate the dendritic structure caused by casting and reduce segregation, creating a uniform element distribution. The insoluble intermediate particles composed of Al, Cu, and Fe were distributed on the grain boundaries with blocks and dots. After extrusion, the grains were flattened and elongated into thin fibers. With increasing extrusion temperature and speed, the misorientation of grains was increased, the degree of dynamic recovery and recrystallization were promoted, and the grain size was decreased. Increasing the extrusion speed properly is beneficial to grain refinement and dynamic recrystallization. The main texture components of the extruded profiles were Y, Cube textures with the orientations of <111>, <100>, and other {111} fibers. With the increasing temperature and speed, the texture types were changed from shear texture to recrystallization texture. The intensity of texture was decreased, while the texture diversity was increased. The hardness, tensile strength and yield strength of extruded profile were greatly enhanced, but the elongation was decreased. The tensile fracture morphology exhibited a large number of dimples, which was considered to be ductile fracture. [ABSTRACT FROM AUTHOR]

• Extruded microstructure and mechanical properties of novel Mg-8.89Li alloy were studied. • Flowing velocity, strain rate and temperature increased with the increase of extrusion speed. • Edge and center zones of the extruded plate exhibited different grain structure. • Extrusion speed significantly affects the microstructure and mechanical properties of Mg-8.89Li alloy. The numerical simulation and experiments were conducted to study the hot extrusion of Mg-8.89Li-0.96Zn alloy. The extrusion process was modelled based on finite element method, and the effects of extrusion speed on the distribution of flowing velocity, effective strain rate, and temperature were clarified. Moreover, the extrusion experiments were carried out at varied extrusion speeds, and both the microstructure and mechanical properties of the extruded alloy were examined. The results showed that the flowing velocity, effective strain and temperature increased with the increase of extrusion speed, and the deformation is more severe in the edge of the extruded plate than that in the center. The grain size is smaller and the degree of dynamic recrystallization is higher in the edge zone. With the increase of extrusion speed, the average grain size in the edge zone increased, while the grain size in the center zone firstly decreased and then increased. When the extrusion speed is 0.5 mm/s, the specimen exhibited the best ultimate tensile property and elongation due to its uniform grain size and relatively more recrystallized grains. The hardness increases from the center to the edge due to the decreasing grain size. [ABSTRACT FROM AUTHOR]

In this paper, a new type of low-cost Mg-3.36Zn-1.06Sn-0.33Mn-0.27Ca (wt %) alloy ingot with a diameter of 130 mm and a length of 4800 mm was fabricated by semicontinuous casting. The microstructure and mechanical properties at different areas of the ingot were investigated. The microstructure and mechanical properties of the alloy under different one-step and two-step homogenization conditions were studied. For the as-cast alloy, the average grain size and the second phase size decrease from the center to the surface of the ingot, while the area fraction of the second phase increases gradually. At one-half of the radius of the ingot, the alloy presents the optimum comprehensive mechanical properties along the axial direction, which is attributed to the combined effect of relatively small grain size, low second-phase fraction, and uniform microstructure. For the as-homogenized alloy, the optimum two-step homogenization process parameters were determined as 340 °C × 10 h + 520 °C × 16 h. After the optimum homogenization, the proper size and morphology of CaMgSn phase are conducive to improve the microstructure uniformity and the mechanical properties of the alloy. Besides, the yield strength of the alloy is reduced by 20.7% and the elongation is increased by 56.3%, which is more favorable for the subsequent hot deformation processing. [ABSTRACT FROM AUTHOR]

Abstract Al/Mg/Al sheet was fabricated by the proposed porthole die co-extrusion and subsequent hot rolling (PCE-R) method. The intermetallic compounds of β-Al 3 Mg 2 and γ-Mg 17 Al 12 were formed in transition layer after PCE-R process, and the thicknesses of β and γ layers became larger at higher rolling temperature or higher reduction ratio. Partial dynamic recrystallization (DRX) occurred in Al layer, and Al layer mainly consisted of shear-typed {111} fiber textures. However, if the rolling reduction is as high as 75%, Al layer exhibited quite different texture components. Mg layer consisted of fine equiaxed grains and several elongated grains, implying the occurrence of near complete DRX. With the increase of rolling temperature or reduction ratio, the number of Mg 17 Al 12 particles in Mg layer was reduced, resulting into larger grain size. Mg layer had strong basal plane texture with c -axis parallel to transverse direction. Al/Mg/Al sheet rolled at 300 °C with 65% reduction exhibited two stress-drop fracture mechanism during tensile test, and it showed excellent tensile strength of 149 MPa, and elongation of 0.13. However, Al/Mg/Al sheet rolled with 75% reduction had inferior tensile properties due to the existence of some cracks after rolling. Graphical abstract Image 1 Highlights • Porthole die co-extrusion and hot rolling was proposed for fabricating Al/Mg/Al sheet. • Thickness of intermetallic compounds increased with increasing rolling temperature and reduction ratio. • Rolling temperature and reduction ratio affected the microstructure of both Al and Mg layers. • Al/Mg/Al sheet rolled at 300 °C with 65% reduction exhibited best tensile properties. [ABSTRACT FROM AUTHOR]

A porthole die co-extrusion (PCE) process was proposed to fabricate the Al/Mg/Al laminate. The results showed that the laminate was successfully extruded without voids or cracks on the Al/Mg interface. The transition layer was formed and its thickness was increased with the increase of temperature. Partial dynamic recrystallization (DRX) occurred in Al layer, and the texture of Al layer has strong E {111}<011> and Y {111}<112> shear-typed components and relative weak Copper {112}<111> and S {123}<634> rolling components. The near complete DRXed grain structure was observed in Mg layer, and the average grain size increases with increasing temperature. Mg layer has strong basal plane texture with (0001) planes parallel to extrusion direction and prismatic planes with random distribution. At lower extrusion temperature, both the Al and Mg matrixes exhibited higher hardness. Furthermore, the hardness of Al/Mg interface is lower than that of the Al and Mg matrix. [ABSTRACT FROM AUTHOR]

Porthole die extrusion of Mg-Al-Zn alloy was conducted using the as-cast, as-homogenized and as-extruded billets. The effects of initial microstructure on grain size, secondary particle, texture and mechanical properties of the extruded profiles were investigated. The results showed that complete dynamic recrystallization (DRX) occurred in welding zone of all profiles, and the profile extruded from as-cast billet had the smallest DRXed grains. Large un-DRXed grains with {10−12} extension twins were found in the matrix zone of the profiles extruded from as-cast and as-homogenized billets. In welding zone, all profiles have a strong basal plane texture with <0001> directions parallel to transverse direction, while the texture intensity and distribution significantly varied with initial billets. The profile obtained from as-extruded billet exhibited inferior tensile properties due to its low solid bonding degree. The hardness distribution in matrix zone of the profiles was not uniform due to the inhomogeneous microstructure. [ABSTRACT FROM AUTHOR]

In this study, the microstructure evolution during solution treatment of extruded Al-Zn-Mg profile containing a longitudinal weld seam was firstly reported. The porthole die extrusion experiment was conducted to obtain the extruded profile. The solution treatment was performed at 470 °C for 15 min, 60 min and 120 min, respectively, and the aging was performed at 120 °C for 24 h. The secondary phase distribution, grain morphology, grain size and texture evolution of welding zone during solution were investigated. Moreover, the hardness and tensile properties after aging were analyzed. The results show that the solution for 15 min is sufficient for the dissolution of MgZn 2 phase, while Al 2 CuMg and Al 23 CuFe 4 phases cannot be dissolved even the solution time is prolonged to 120 min. The main texture components of {110}<111> and {110}<115> are formed after extrusion process, and these textures are remained after solution treatment. With increasing solution time, the intensity and volume fraction of texture firstly increases and then decreases. Furthermore, both the average size and aspect ratio of grains in welding zone increase with increasing solution time. The best hardness, tensile strength and elongation was obtained in the Al- Zn-Mg profile after solution treated for 15 min. [ABSTRACT FROM AUTHOR]

In this study, the dynamic recrystallization (DRX) behavior of an Al-Zn-Mg alloy during porthole die extrusion process was studied. Firstly, the hot compression tests were conducted at varied temperatures and strain rates. The constitutive equation was established based on modified Arrhenius and Johnson-Cook models, respectively, and DRX kinetic equation was established based on modified Avrami model. Secondly, transient simulation using the established constitutive and DRX kinetic equations was performed for porthole die extrusion process. Finally, in order to verify the accuracy of simulated results, the extrusion experiment was conducted and the microstructure was analyzed. The results show that both the strain compensated Arrhenius model and modified Johnson-Cook model can accurately describe the flow stress of Al-Zn-Mg alloy at elevated temperature. Higher deformation temperature and lower strain rate are favorable for the occurrence of DRX. The volume fraction of DRX at the zones close to bridge and porthole wall is much higher than that in the other zones, and this kind of inhomogeneous DRX behavior is mainly attributed to varying distribution of stain. According to the experimental results, several subzones with different microstructures were identified. Importantly, the simulated DRX volume fraction shows good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

In this study, the optimal carbon fiber/matrix (CF/matrix) interfacial adhesion was explored by tailoring sintering pressures, aiming to enhance the ultimate tensile strength (UTS) of CF/Mg composites. With increasing the pressure, the interfacial shear strength (IFSS) gradually increased from 28.8 MPa to 43.6 MPa. Remarkably enhanced UTS (152 MPa) of the composite was achieved, which was 120.3 % higher than that of the matrix, through optimizing the IFSS to 39.7 MPa. Correspondingly, the main failure mechanism was fiber pulling-out and direct fiber-cutting. Whereas, excessive IFSS (43.6 MPa) deceased the UTS of the composite, with the dominant failure mechanism of direct fiber-cutting. [Display omitted] • The CF/matrix interfacial adhesion was effectively optimized for enhanced mechanical properties of CF/Mg composites. • With an optimal interfacial adhesion, remarkable enhanced UTS (152 MPa) was achieved, which was 120.3 % higher than matrix. • An optimal interfacial adhesion contributed to effective load transfer and more harmful energy absorption at the interface. [ABSTRACT FROM AUTHOR]

The TiB 2 /6061Al composite profile with sound welding quality and good mechanical properties was fabricated by porthole die extrusion. The effects of TiB 2 particles on the microstructure evolution and mechanical properties were investigated, and the welding mechanism was clarified. The results indicated that the weld seam in both 6061Al and TiB 2 /6061Al profiles disappeared as porthole die extrusion progressed. TiB 2 particles refined the grain structure by promoting the occurrence of dynamic recrystallization through particle stimulated mechanism (PSN-DRX) and inhibiting the grain growth. The interface between TiB 2 particles and 6061Al matrix was in good bonding status and modified by MgAl 2 O 4 phase. The welding mechanism in the area far away from TiB 2 particle is mainly the nucleation and growth of discontinuous dynamic recrystallization (DDRX) initiated by the bulging mechanism. In the vicinity of TiB 2 particle, the nucleation of DDRX is suppressed due to the formation of particle deformation zone containing high-density dislocations, and the nucleation and growth of PSN-DRXed grains become the dominated welding mechanism. The strong β-fiber texture and relatively weak α-fiber texture were observed in both 6061Al and TiB 2 /6061Al profiles, while the addition of TiB 2 particles greatly reduced the intensity of main textures, which in turn weakened the differences in tensile strength at different locations. TiB 2 particles also contribute to better mechanical performances due to the effects of grain refining, load transfer and dislocation strengthening. [Display omitted] • TiB 2 /6061Al composite profile with sound welding quality was achieved by porthole die extrusion. • TiB 2 /6061Al interface was in good bonding status and modified by MgAl 2 O 4 phase. • Sound welding was realized through the nucleation and growth of dynamic recrystallized grains. • Grain refining, load transfer and dislocation strengthening are the main strengthening mechanisms. [ABSTRACT FROM AUTHOR]

A novel method based on hot press sintering was proposed to fabricate the Al/Ti laminated composite, and the effects of sintering parameters on microstructure, interfacial structure, and mechanical properties were thoughtful examined. The results showed that insufficient sintering caused obvious voids and cracks at Al/Ti interface. With the increase of temperature or holding time, a good metallurgical bonding without defects was achieved, and both the recrystallization fraction and grain size of α phase in Ti layer increased, accompanied by the transformation of α to β phase and growth of intermetallic phase. The microstructure variation of Al layer is not evident with changing the sintering parameters. Due to the relatively low formation energy, the nanoscale TiAl 3 phase with massive stacking faults formed at Al/Ti interface, and lots of dislocations existed at Al layer near the interface. The voids and cracks formed at Al/Ti interface led to the premature failure of laminate. On the basis of the metallurgical bonding and small TiAl 3 phase, the high fraction and texture intensity of α phase were the dominated strengthening factors. Moreover, the back stress generated at Al/Ti interface contributes to an extra strengthening. The superior mechanical properties of Al/Ti laminate with a tensile strength of 670.9 MPa and a fracture strain of 0.33 were obtained with the sintering temperature of 600 °C and holding time of 2 h. [Display omitted] • A superior combination of strength and fracture strain of Al/Ti laminate was obtained by hot press sintering. • Grain size, recrystallization fraction, and texture intensity of α phase were sensitive to sintering parameters. • Nanoscale TiAl 3 phase with massive stacking faults formed toward Al layer at Al/Ti interface. • Achieving metallurgical bonding and minimizing the size of TiAl 3 facilitate a strong strengthening effect. [ABSTRACT FROM AUTHOR]

• The dynamic evolution of T 1 phase during the hot deformation of Al-Cu-Li alloy has been completely revealed for the first time. • The mechanism interaction of T 1 phase with dislocation and grain boundary is elucidated. • The dynamic precipitation of T 1 phase greatly promoted the CDRX behavior by pinning dislocation walls and sub-grain boundaries. The T 1 phase is the highest density and most prominent strengthening effect precipitate in Al–Cu–Li alloys, and it undergoes a complex dynamic evolution during hot deformation, which has significant effects on microstructure development and hot working. This study comprehensively characterizes and analyzes the dynamic evolution of the T 1 phase at 400 °C/0.01 s−1 and its influence on continuous dynamic recrystallization (CDRX). The results indicate that the T 1 phase successively undergoes coarsening, fracture, dissolution, dynamic precipitation, recoarsening, and spheroidization during deformation. A shear-coupled diffusion mechanism is proposed to explain the ultrafast coarsening rate of the T 1 phase in early deformation. During the dynamic precipitation of the T 1 phase, an anomalous inhomogeneous size and spatial distribution of the T 1 phase are observed, and a high number density of fine T 1 phases form in the matrix (with a denser, thinner and shorter size at the dislocation wall). The dynamically precipitated T 1 phase is affected by the octahedral slip system during the coarsening process and exhibits a selective ripening phenomenon. The T 1 phase formed by aging increases the inhomogeneity of the deformation and induces many substructures intragranularly, decreasing the percentage of CDRX grains but increasing the CDRX potential. Conversely, the dynamically precipitated T 1 phase and its evolution accelerate CDRX development by promoting the transformation of LAGBs to HAGBs. In addition, the effects of dynamically evolving precipitates on the dislocations and formation modes of LAGBs at various deformation stages are elucidated. The results can provide valuable insights into the regulation of microstructure, and the development of high-performance Al–Cu–Li alloys, and also offer a theoretical and experimental basis for microstructure modeling. [Display omitted] [ABSTRACT FROM AUTHOR]

• FSSW of Al and CFRTP joint were studied with surface treatment and interfacial adhesion. • The combination of laser ablation and interfacial PA6 film significantly enhanced the interfacial bonding of the joint. • A bond force of 10.282 kN was shown for the Al/CFRTP joints at FSSW 2000 rpm–3 mm–10 s. The multiple material design of lightweight structural components of new energy vehicles imposes high demands on the joint of Al alloy and CFRTP composite. This study explored the fabrication of high joint strength between Al alloy 6061 and CFRTP PA6 composites through the laser ablation on Al alloy surface and friction stir spot welding (FSSW) process. By experimental optimization of the FSSW parameters, including rotational speed, displacement, and dwelling time, a remarkable tensile shear force of 10.282 kN was achieved under the rotational speed of 2000 rpm, displacement of 3 mm, and dwelling time of 10 s. The interfacial morphology of the Al alloy/CFRTP joint was characterized in detail. The microstructure analysis revealed a number of physical anchoring areas formed at the joint interface of laser-ablated Al alloy and CFRTP PA6. The PA6 resin of the CFRTP could be fully melted and effectively fill the grooves on the laser-ablated Al alloy surface due to the compression load and heat output at a high rotational speed and dwelling time. [ABSTRACT FROM AUTHOR]

The solution experiments on cold rolled 2024 Al sheet with a 1070 Al coating were carried out at various temperatures and holding time. The effects of solution parameters on the microstructure evolution and mechanical properties were studied. The results showed that the alloying elements diffused from the 2024 Al matrix to the 1070 Al coating, following the peak-valley pattern. The cold rolled 2024 Al sheet mainly have the second phases of Al 2 Cu, S (Al 2 CuMg), Si, Mg 2 Si, and the impurities of AlFeMnSi, AlCuFeMnSi, AlCuFeMn, and the amount of them was reduced with increasing solution temperature or holding time. T (Al 20 Cu 2 Mn 3) had precipitated before aging, and only the Cu–Mg clusters were formed during the natural aging, which should be the main strengthening mechanism. The grain structure was elongated during cold rolling, while the static recrystallization and grain growth occurred during the solution treatment. The ultimate tensile strength, yield strength and elongation were gradually enhanced with increasing the solution temperature to 510 °C. When the solution temperature is further increased to 530 °C, the elongation was obviously decreased due to the over-burning. Moreover, it was found that the solution temperature had much stronger effects on the mechanical properties than that of the holding time. Image 1 • Effects of solution parameters on naturally aged EN AW 2024 Al sheet were studied. • Most of the second phases dissolved during solution, while the Fe containing phases were remained. • High solution degree facilitated the formation of Cu–Mg clusters during natural aging. • UTS, YS and elongation of naturally aged 2024 Al reached the peak values after solution treated at 510 °C. [ABSTRACT FROM AUTHOR]

The abnormal grain growth of ZK60 alloy during porthole die extrusion was studied. The results indicated that the abnormal grains (AGs) discontinuously formed along the weld seam, due to the growth priority of some grains and the restriction on normal grain growth. The grain boundaries with large misorientation angles owned high energy and mobility, and the different sub-grain structures between AGs and normal grains (NGs) provided the driving force for AGs to sweep out NGs. Moreover, the pining effects of precipitates restricted the growth of NGs, while rare precipitates formed on AGs boundaries. In case of NGs, the grain size was firstly refined due to dynamic recrystallization, and then it increased due to the grain growth. <0001>//TD basal plane and <11–20>//ED fiber textures formed, and then the fiber texture rotated 30° around c -axis by {10-10} <1–210> prismatic slip, resulting in the transformation into {0001} <10-10>. The formation of AGs deteriorated the tensile properties. Moreover, high extrusion temperature or speed increased the sizes of AGs and NGs, and decreased the number of precipitates, which caused the decreasing hardness, yield/tensile strength, and elongation. • Abnormal coarse grains with an orientation of <11–20>//ED discontinuously located on the weld seam. • The occurrence of abnormal coarse grains depends on texture, subgrain structure and precipitates. • The size of abnormal coarse grains increases with increasing extrusion temperature and speed. • The existence of abnormal coarse grains severely deteriorates the mechanical properties. [ABSTRACT FROM AUTHOR]

The extrusion parameters greatly influence the microstructures of aluminum alloys, and further determine the mechanical properties of the final products. In this work, using a self-designed experimental device, a series of extrusion experiments was conducted to investigate the influence of the extrusion parameters on the microstructure, crystallographic texture, and second-phase particles in the Al-Mg-Si aluminum alloy (AA6N01), which is widely applied in the bodies of high-speed trains. Firstly, the billet discard in the press container was taken out for analyzing the material flow and microstructural evolution during the extrusion process. The results showed that continuous dynamic recrystallization occurred, and the initially coarse equiaxed grains in the as-homogenized billet evolved gradually into fine equiaxed grains at the die exit due to their dynamic recovery and dynamic recrystallization. More importantly, coarse grain layers were observed on the surface of the extruded profiles under specific extrusion conditions (460 °C/48 mm/min and 520 °C/48 mm/min). Then, the textures on the surface and at the center of the profiles were analyzed under different extrusion conditions by electron backscatter diffraction. The results showed that the textures of all the extruded profiles were mainly along <100> and <111 > , but the texture intensity was higher at the profile's center than that on the surface under the same extrusion condition. Finally, the second-phase particles in the as-homogenized billet and as-extruded profiles were compared and analyzed. The Fe-rich particles were broken under deformation conditions and their sizes decreased during the extrusion process. However, they were all still distributed on the grain boundaries after deformation, and the composition and content remained unchanged. The Mg 2 Si particles served as the main strengthening phase in AA6N01, and they were greatly aggregated as the extrusion temperature increased and the extrusion speed decreased. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The novel hot extrusion method using electric pulse was proposed on Mg alloys. • The coarse grained bands disappeared and the grain size was refined to 2.25 μm. • The second phase became more dispersive and its size was obviously reduced. • Both the properties of UTS and YS were enhanced by electric pulse of 70 V/250 Hz. Abstract A novel method was proposed to refine the grain structure and enhance the strength of extruded AZ91 alloys by electric pulse. The grain structure was refined to the average size of 2.25 μm due to the strong athermal effects. The size of Mg 17 Al 12 phase was greatly reduced and its distribution became much more dispersive. The strong {0 0 0 1} basal texture with c -axis parallel with normal direction appeared, and its intensity was slightly increased. The specimen extruded by electric pulse with the peak current density of 117.4 A/mm2 exhibited the highest yield strength of 221 MPa and tensile strength of 384 MPa. [ABSTRACT FROM AUTHOR]

Abstract The dynamic recrystallization (DRX) behavior and microstructure evolution of an Al-Mg-Si aluminum alloy (AA6N01) during hot deformation are investigated by experiments and mathematical modeling. Based on hot compression tests under different strain rates and temperatures, the type of dynamic recrystallization are firstly investigated by EBSD analysis. It is observed that DRX occurs under all examined conditions, however, the type of DRX is associated with the deformation temperature at the strain level of about 1.5. Then considering the deformed and recrystallized behaviors, a grain size evolution model is established to predict the microstructure evolution during hot deformation. (1) According to the dislocation work hardening theory, the DRX kinetic model is built to predict the distribution of DRX. (2) Taking the effects of deformation temperature and strain rate into account, the DRX grain size model is built to predict the equiaxed recrystallized grain size. (3) By combining the experimental observations with numerical simulation, the deformed grain size model is established to predict the elongated grain size evolution. Finally, by integrating above three models, the grain size evolution model is established to predict the microstructure evolution of AA6N01 during high-temperature deformation and is validated by comparing the predicted grain size with experimental observations during hot compression and hot extrusion, respectively. Graphical abstract Image 1 Highlights • Eight material parameters of a physical constitutive model are identified for AA6N01. • The type of DRX of AA6N01 depends highly on the deformation temperatures. • A grain size evolution model is established to predict the microstructure evolution. • The bulit grain evolution model is well validated by hot compression and extrusion. [ABSTRACT FROM AUTHOR]

Laminated structure with alternating hard and soft layers can exhibit superior mechanical properties, while the quality of interlayer bonding is difficult to be controlled. This study proposed a hot press sintering process using Al sheet and Al-TiB 2 powder mixture as the raw materials to fabricate Al/Al-TiB 2 laminated composites with different stacking sequences. The results indicate that both Al/Al-TiB 2 and Al/TiB 2 interfaces are well bonded, and a mass of stacking faults as well as dislocation loops locate at the interfaces. Al-TiB 2 layer always has much smaller grains than Al layer, and its grain size can be further reduced by increasing the TiB 2 content. The bending properties of laminated composites are strongly affected by stacking sequence. A high bending strength is achieved if Al-TiB 2 act as interlayer, and a superior toughness can be realized if Al act as interlayer. The reinforcing effects of Al-TiB 2 layer and extra-strengthening of tailored laminated bimodal structure contribute to enhancing the bending strength. The induced geometric necessary dislocations at Al/Al-TiB 2 interface facilitate the release of stress concentration and coordinate the deformation between layers, and the formed tunnel cracks absorb extra fracture energy, resulting in improvement of toughness. [Display omitted] • The interface between Al and Al-TiB 2 layers is uniform and tightly bonded without defects. • Induced GNDs facilitate the release of stress concentration and coordinate deformation between layers. • Strain transferring, strain partitioning, and tunnel cracks contribute to enhancing toughness. • Improvement of strength is achieved arising from reinforced particles and laminated bimodal structure. [ABSTRACT FROM AUTHOR]