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For years, coated metal sheets have been used in cookware manufacturing. This paper focuses on employing experimental and numerical analyses to determine the quality and formability of commercially available polytetrafluoroethylene (PTFE)‐coated aluminium sheets. For this purpose, examinations of the coating's microstructure, hardness, and friction coefficient through nano‐indentation and scratch tests, were investigated. Tensile test was performed to obtain some mechanical characteristics of the coated aluminium sheets. Moreover, the forming limit curve for the studied material was established by conducting Nakazima test, covering both negative and positive domains of minor strain. The influence of sheet thickness on formability was investigated since using 2 mm and 1 mm thick sheets in this work. Finally, the limits of deep drawing process using the finite element method with Abaqus software was studied. [ABSTRACT FROM AUTHOR]

Incremental sheet forming has emerged as an excellent alternative to other material forming procedures, incrementally deforming flat metal sheets into complex three-dimensional profiles. The main characteristics of this process are its versatility and cost-effectiveness; additionally, it allows for greater formability compared to conventional sheet forming processes. Recently, its application has been extended to polymers and composites. The following review aims to present the current state of the art in the incremental sheet forming of polycarbonate, an outstanding engineering plastic, beginning with initial studies on the feasibility of this process for polymers. Attention is given to the advantages, drawbacks, and main applications of incrementally formed polycarbonate sheets, as well as the influence of process parameters and toolpath strategies on features such as formability, forming forces, deformation and failure mechanisms, geometric accuracy, surface quality, etc. Additionally, new hybrid forming methods for process optimisation are presented. Finally, a discussion is provided on the technical challenges and future research directions for incremental sheet forming of polycarbonate and, more generally, thermoplastics. Thus, this review aims to offer an extensive overview of the incremental forming of polycarbonate sheets, useful to both academic and industrial researchers working on this topic. [ABSTRACT FROM AUTHOR]

Metallization, a process for applying anti-corrosion coatings, has advantages over hot-dip galvanizing, such as reduced thermal stress and the ability to work "in situ". This process consists of the projection of a protective metal as coating from a wire as application material, and this wire is obtained by multi-stage wiredrawing. For the metallization process, a zinc–aluminum alloy wire obtained by this process is used. This industrial process requires multiple stages/dies of diameter reduction, and determining the optimal sequence is complex. Thus, this work focuses on developing models with the aim of designing and optimizing the wiredrawing process of zinc–aluminum (ZnAl) alloys, specifically ZnAl15%, used for anti-corrosion applications. Both analytical models and numerical models based on the finite element method (FEM) and implemented by computer-aided engineering (CAE) software Deform 2D/3D v.12, enabled the prediction of the drawing stress and drawing force in each drawing stage, producing values consistent with experimental measurements. Key findings include the modeling of the material behavior when ZnAl15% wires were subjected to the tensile test at different speeds, with strain rate sensitivity coefficient m = 0.0128, demonstrating that this type of alloy is especially sensitive to the strain rate. In addition, the optimal friction coefficient (µ) for the drawing process of this material was experimentally identified as µ = 0.28, the ideal drawing die angle was determined to be 2α = 10°, and the alloy's deformability limit has been established by a reduction ratio r ≤ 22.5%, which indicates good plastic deformation capacity. The experimental results confirmed that the development of the proposed models can be feasible to facilitate the design and optimization of industrial processes, improving the efficiency and quality of ZnAl15% alloy wire production. [ABSTRACT FROM AUTHOR]

Conventional sheet metal forming processes have problems like low formability, non-uniform strain distribution, spring back, wrinkling, etc. High velocity processes like electrohydraulic forming can deform sheets at high strain rate and have capability to tackle such problems associated with conventional forming operations to a greater extent. Forming limit diagram (FLD) characterizes sheet deformation as measure of formability. Punch stretch test (PST) can assess formability of sheet in conventional low strain rate process, but no standard method is available to determine FLD at high strain rate. So in the present work, an experimental setup has been developed to characterize sheets at high strain rate using hydraulic forming process with a 40 kJ capacitor bank. A similar corresponding standard setup for punch stretch test is also developed for comparative study of formability with respect to dome height, forming limit curve, and strain distribution. Formability of aluminum alloy AA5754 is determined at quasi-static and high strain rates, and comparative analysis is reported for whole state of strain using dog bone samples of width ranging from 10 to 120 mm. An estimate of electrohydraulic forming parameters for high strain test of the Al alloy using the given setup is also determined. Study of comparative strain distribution behavior of samples of different widths is also carried out. Comparative analysis shows that there is an improvement in formability and strain distribution behavior of the alloy deformed using EHF as compared to PST. [ABSTRACT FROM AUTHOR]

Duplex stainless steel (DSS) 2205 finds wide application in aircraft industries and for surgical implants. However, the formability of 2205 steel sheets is limited under normal conditions, requiring hot-working to enhance strain hardening at lower temperatures. Furthermore, there is a lack of research on the single point incremental forming process (SPIFP) applied to DSS 2205. Hence, the current study aims to explore the fracture characteristics of 2205 steel sheets using SPIFP, while varying several parameters such as tool type, tool diameter, speed, feed rate, and vertical step down. Optimal process parameter selection holds significant importance due to its potential for cost reduction and enhancement of quality. This choice involves determining suitable process parameters while considering multiple conflicting factors, necessitating the application of the multiple criteria decision-making (MCDM) approach. Hence, this work addresses the MCDM challenge using the additive ratio assessment (ARAS) and complex proportional assessment (COPRAS) techniques. The experiment carried out with two different forming tools such as hemispherical-ended forming tool and ball-ended forming tool, assessment carried out by varying the stated independent parameters. The dependent parameters include straight groove depth, wall angle depth, spring back, formability, and surface roughness. The SPIFP alternatives are assessed using the aforementioned two techniques, and the outcomes are subsequently analyzed. The best possible arrangement was determined using ARAS and COPRAS methods to achieve both maximum and minimum values for all the responses. This arrangement was identified with the hemispherical-ended forming tool and the specific set of process parameters: a tool diameter of 10 mm, a feed rate of 600 mm/min, a speed of 200 rpm, and a vertical step down of 0.6 mm. In 77.78% of instances, the rankings from ARAS are in agreement with the rankings from COPRAS. Notably, the lower and higher orders of rankings are the same, adding an intriguing dimension to the observation. However, the patterns of different dependent variables, influenced by the diversity of independent variables, were not consistent. These intricate mechanisms have been recognized and documented. [ABSTRACT FROM AUTHOR]

Hydroforming is a modern metal-forming process prominently used in the shipbuilding, aerospace, and automotive industries for forming lightweight, complex-shaped geometries due to their inherent process benefits. But this process faces challenges such as limited material selection, high tooling costs, and complex process control for obtaining a defect-free part with uniform thickness. Researchers are constantly innovating and advancing hydroforming technologies to overcome these limitations. This work reviews emerging tube and sheet hydroforming technologies, considering parametric effects and design considerations, particularly for micro-domain applications. Further, a wider acceptance of the hydroforming process in different industries is explored by discussing the studies that tried to improve the efficiency and quality of the hydroforming process. This study observed that better formability could be achieved in hydroforming with appropriate intermediate heat treatment, proper lubrication, the correct design of loading paths, and temperature distribution. In tube hydroforming, wrinkles, necking, and cracking observed to be largely reduced by properly selecting the internal pressure and feeding. The precise protrusion height and uniform thickness at different joint cross-sections in tube forming are found to be significantly influenced by the strain-hardening exponent, loading path, and friction coefficient. Electrohydraulic forming is found being increasingly used due to its higher productivity and lower product cost. However, further research is required to achieve complex sheet geometries with sharp corners. This research emphasizes that advanced research, artificial intelligence integration, and the exploration of alternative materials can improve the performance of the hydroforming process. [ABSTRACT FROM AUTHOR]

AbstractAuxetic materials are characterized by a negative Poisson’s ratio (NPR), which expands when stretched and shrinks when compressed. Due to the synclastic curvature of auxetics, they have good formability. These properties make them useful in applications requiring formability, such as composites, fashion and clothing, medical, protective, and sports fields. In this research, auxetic weft-knitted fabrics based on foldable structures were knitted. The effect of structural parameters including fabric pattern, yarn count, and loop length on the formability of auxetic weft-knitted fabrics was investigated and compared to plain weft-knitted fabric (Jersey). Auxetic fabrics with three distinct patterns and three different loop lengths were knitted using polyester yarns of varying three counts. Then, the formability experiment was conducted using the hemisphere mold, and the forming energy of fabric samples was obtained. The results demonstrated that auxetic fabrics exhibit superior formability to conventional (non-auxetic) fabrics, attributed to their synclastic curvature. Among the auxetic fabrics, those with larger zigzag angles, finer yarn counts, and larger loop lengths showed higher formability. These findings enhance the potential applications of auxetic fabrics in various industries such as medical and protective, emphasizing their ability to conform to complex shapes with minimal wrinkling. [ABSTRACT FROM AUTHOR]

In this study, the thermoforming formability of continuous glass fiber-reinforced polypropylene (CGFRPP) laminates below the melting temperature were investigated. The forming limits of CGFRPP laminates were explored using flexural tests, Erichsen tests and deep drawing tests. The failure mechanism of CGFRPP in thermoforming was investigated by observing typical failure specimens using a microscope. The results show that the flexural performance and Erichsen performance are optimal at 130 °C and 2 mm/min. At 160 °C and 100 mm/min, the deep drawing performance is optimal. The restriction of fibers by the matrix is affected by the deformation temperature, and the creation of defects is affected by the deformation rate. During forming, the CGFRPP laminates undergo shear and extrusion deformations, resulting in wrinkles, delamination, and fiber aggregation. [ABSTRACT FROM AUTHOR]

Featured Application: This paper develops an innovative post-weld composite treatment process, which can significantly improve the formability of aluminum alloy tailor welded blanks compared with the traditional single post-weld treatment method. The mechanical properties and cross-sectional geometric dimensions of the fusion zone (FZ), heat affected zone (HAZ), and base metal (BM) of 6xxx series aluminum alloys are inconsistent after filler wire welding, which reduces the formability of aluminum alloy tailor welded blanks (TWBs). This paper proposes a post-weld cold rolling-solution heat treatment (PWCR-SHT) composite process, and the effects of weld excess metal, plastic deformation, and SHT on the formability of aluminum alloy TWBs are studied. The results show that the PWCR-SHT composite process eliminates the weld excess metal and internal pores, reduces the stress concentration at the weld toe, eliminates the local strain hardening behavior, and causes recrystallization in the FZ region. The cupping value of aluminum alloy TWBs using SHT is 105% of BM, in comparison, the cupping value of aluminum alloy TWBs using the PWCR-SHT composite process is 119% of BM, which is the result of the combined effect of geometric dimensions consistency and mechanical properties consistency. [ABSTRACT FROM AUTHOR]

The hybrid method, known as Incremental Sheet Hydro Forming (ISHF), is a combination of the techniques of Incremental Sheet Forming and Sheet Hydro-Forming. The primary concern identified in the incremental sheet forming formation strategy relates to the potential failure of the product due to the thinning of the sheet and subsequent springback. In response to the issue of sheet failure resulting from thinning, a revised iteration of the integrated sheet hydroforming (ISHF) method was proposed. The revised version of the ISHF process has demonstrated notable improvements in the malleability of the material. The ISHF technique entails the movement of a single ball tool along one side of the sheet's surface, while hydraulic support is applied on the opposite side through the use of pressurized hydraulic fluid. The present study sought to investigate the impact of hydraulic support on metal formability and thickness distribution. In addition, a modified variant was also considered. The experimental results are in close agreement with the predictions made by the analytical models. The strain distribution throughout the length of deformation for the sheet has been calculated. The surface quality of the products was found to be satisfactory and a preliminary simulation has been performed. This study examines the influence of process factors, specifically spindle speed (1000/1500/2000 RPM), feed rate (400/600/800 mm/min), tool diameter (8/10/12 mm), and step-down (0.2/0.4/0.6 mm), on the cone-shaped feature at the specimen of aluminum alloy A 5010. The results demonstrated that, through analysis of variance, the most influential factor in the distribution of thickness was speed. Regarding formability, the rate of change was found to be the highest at 50%. [ABSTRACT FROM AUTHOR]

This study investigates the cold formability of Vanadium microalloyed steel DIN 30MnVS6 by characterizing the material's mechanical behavior at room temperature and constructing the fracture-forming limit diagram. A carefully selected set of tests was conducted to establish formability limits in terms of local deformations. Concurrently, finite element numerical analysis was employed to deepen the understanding of the influence of local stress and strain states on the material's ability to deform without fracturing. The effects of geometric conditions, lubrication, and friction on formability were thoroughly investigated. Surface stress analysis highlighted the close relationship between formability and the stress state induced by process parameters. The construction of the fracture-forming limit diagram revealed that DIN 30MnVS6 exhibits formability comparable to steels widely used in cold forging. The steel proved to be a promising option for applications in this process, providing a viable alternative in terms of formability. [ABSTRACT FROM AUTHOR]

Tailor weld blank (TWB) is preferred in different components of automobiles to reduce weight of the vehicle. However, TWBs have lower formability than sheets because of increased hardness and strength of weld region. Hence, in this work, detailed formability analysis of TWB of AISI304 is done and compared with as-received sheets along with microstructural correlation. Forming limit diagram for as-received sheet, TWBs are determined. Strain hardening exponent value of as-received sheet is 0.381, unweld region and weld region of TWB is observed to be 0.362 and 0.301, respectively. Numerical simulations were also done for predicting the FLC of TWB of AISI304 with the help of PAM STAMP 2 G solver. TWB showed lower formability than as-received sheets. Similarly, predicted FLD for TWB is almost coinciding with the experimental value. Similarly, optical micro-structure studies were also analysed for as-received sheet, unweld region and weld region of TWB, which showed fully austenitic structure with random grain orientations. At the same time, it was found that strain path chosen for FLD determination has a strong influence on microstructure evolution. [ABSTRACT FROM AUTHOR]

In order to understand the formability of as-received tempered commercial pure titanium grade 2 foils (CP Ti Gr2) with a thickness of 38 µm, a series of micro limited dome height (µ-LDH) tests were conducted in quasi-static speed (0.01 mm/s) at room temperature without the use of a lubricant. A technique developed at NIU was also used to create micro-circular grids (ϕ50 μm) on the as-received material. The forming limit curve (FLC) of the CP Ti Gr2 foils was obtained through the proposed µ-LDH test. For having mechanical properties of the CP Ti Gr2 foils for LS-Dyna FEA (Finite Element Analysis) simulations, a series of tensile tests in three directions were also conducted at room temperature with the same speed. The obtained FLC has been validated using a micro deep drawing case study in which both FEA simulations and experiments were conducted and compared. It has been proven in this study that the FLC obtained using the proposed µ-LDH test can be used for an extremely thin sheet-metal-forming process by the automotive, aerospace, medical, energy, and electronic industries, etc., right away for product design, forming process development, tool and die designs, and simulations, etc. [ABSTRACT FROM AUTHOR]

This study thoroughly investigates the influence of anisotropy on the formability of 2024-T3 aluminum alloy sheets using advanced techniques such as digital image correlation (DIC) and Marciniak tests. A key finding is the relatively small variation in anisotropy values across different strain paths and orientations, contrasting with more significant variations reported in other studies. Tests were conducted on nine samples with various geometries to induce specific strain paths, including uniaxial, plane, and balanced biaxial strains, oriented in different directions relative to the rolling direction. The study also provides a detailed analysis of microstructural and mechanical characteristics, such as precipitate distribution and anisotropy behavior, which are crucial for understanding the relationship between microstructure and material formability. The results show that while anisotropy impacts deformation capacity, the differences in formability among the directions were minimal, with slightly greater formability observed in the diagonal direction. These findings are compared with forming limit curves (FLCs), offering an integrated view of how relatively uniform anisotropic properties influence formability. These insights are essential for optimizing the processing and application of 2024-T3 alloy in industrial contexts, emphasizing the importance of understanding anisotropy in the design of metal components. [ABSTRACT FROM AUTHOR]

The 18th International Conference on Aluminium Alloys (ICAA18) was held in Toyama, Japan from September 4 to 8, 2022, and the special issue entitled "Aluminium and Its Alloys for Zero Carbon Society" was published on Materials Transactions in February 2023 (Vol. 64, No. 2). The biennial conference covered a wide range of current trends in aluminium research; e.g. "modeling and simulation", "casting, solidification, recycling and refining", "additive manufacturing", "foams and composite materials", "mechanical properties and advanced processing", "thermomechanical processing, texture and recrystallization", "heat treatment, phase transformation and precipitation", "corrosion and surface treatments", "joining, emerging processes and multi material" and "advanced characterization". This article briefly reviews selected papers from the conference with significant experimental outcome and discussion on aluminium alloys. The author hopes that these papers are useful for all the researchers who develop next-generation technologies and materials concerning aluminium alloys. [ABSTRACT FROM AUTHOR]

Zircaloy-4 (Zr-4) sheets are widely used in nuclear industry as assembly structural parts due to its low neutron absorption cross, excellent corrosion resistance and mechanical properties. The initial texture of Zr-4 has great influence on the formability of the sheet. In this paper, the texture evolution with its related deformation mechanism have been analyzed for Zr-4 during stamping process. Finite element model (FEM) was built to achieve the strain path for various locations on the longitudinal section. Modeling accuracy has been validated with the comparison of crack location and experimental thickness distribution. The effect of initial texture on the mechanical property and forming limit curves were discussed. At last, FEM combined with visco-plastic self-consistent (VPSC) modeling was built to predict the effect of different initial texture on deformation modes for Zr-4 in sheet forming process. The results show that smaller initial Kearns factor in normal direction lead to lower stress-strain curves with higher hardening exponents (n value). The cracking strain path near punch corner followed at first plane strain path, then changing to biaxial stretching strain path. It went beyond the forming limit curves (FLC) firstly with normal Kearns factor of 0.71. With the initial normal Kearns factor decreasing to 0.68, the strain paths always remain in the safe region without exceeding FLC. Lower normal Kearns factor induced better formability for Zr-4 sheet with higher prismatic slip. It is expected that this investigation will be helpful to optimize the initial texture, which will be more appropriate for forming process.

In this study, the formability of the AZ31B magnesium alloy sheets was investigated in combination of experiment and CPFEM modelling. The deformation mechanisms during the Erichsen forming were revealed and the effect of the related parameters were discussed. It was shown that the simulation results based on the normalized Cockcroft-Latham criterion are consistent with the experimental results. The maximum stress and strain concentrate at the center of dome, and exhibit an elliptical distribution shape. The difference of asymmetry situation between the sheets results from the different textures. The basal slip is the dominant mode, and the prismatic slip is also active to accommodate plastic strain in sheet plane. The relative activity of the pyramidal slip is low, but very effective to accommodate the plastic strain in thickness direction. The sheet with higher relative activity of the prismatic and pyramidal slips exhibit higher formability. The sheet thickness influences the formability through changing the stress-strain response, as well as the orientation-relationship between stress state and grains which can affect the deformation mechanisms. The formability depends on the plastic strain accommodation ability that is comprehensively related to the averaged plasticity, orientation-relationship between stress state and grains, r-value and n-value. CPFEM modeling is convenient pathway to predict the formability.

Abstract Hydroforming is a modern metal-forming process prominently used in the shipbuilding, aerospace, and automotive industries for forming lightweight, complex-shaped geometries due to their inherent process benefits. But this process faces challenges such as limited material selection, high tooling costs, and complex process control for obtaining a defect-free part with uniform thickness. Researchers are constantly innovating and advancing hydroforming technologies to overcome these limitations. This work reviews emerging tube and sheet hydroforming technologies, considering parametric effects and design considerations, particularly for micro-domain applications. Further, a wider acceptance of the hydroforming process in different industries is explored by discussing the studies that tried to improve the efficiency and quality of the hydroforming process. This study observed that better formability could be achieved in hydroforming with appropriate intermediate heat treatment, proper lubrication, the correct design of loading paths, and temperature distribution. In tube hydroforming, wrinkles, necking, and cracking observed to be largely reduced by properly selecting the internal pressure and feeding. The precise protrusion height and uniform thickness at different joint cross-sections in tube forming are found to be significantly influenced by the strain-hardening exponent, loading path, and friction coefficient. Electrohydraulic forming is found being increasingly used due to its higher productivity and lower product cost. However, further research is required to achieve complex sheet geometries with sharp corners. This research emphasizes that advanced research, artificial intelligence integration, and the exploration of alternative materials can improve the performance of the hydroforming process.

In pursuit of newer lightweight components, clad sheets emerge as a solution to meet the demand for automotive and aerospace applications. The present work focuses on the effect of warm forming temperature on the tensile properties, microstructural characteristics, formability, and residual stress of a two-ply clad sheet composed of SS430 and AA1050 layers. Tensile properties of the clad sheet and individual components are determined through testing of laser cut specimens as per standard at ambient and elevated temperatures (220 °C). These tensile properties are used in the material model for prediction of failure in Erichsen cupping experiments through simulations. At 220 °C, the yield and ultimate tensile strengths of clad sheets are found to decrease by approximately 10% and 18%, respectively, but ductility is observed to increase by almost 5%. Electron backscatter diffraction analysis is done to measure and evaluate the microstructural characteristics of the clad material after the tensile deformation at both temperatures. The kernel average misorientations measured from electron backscatter diffraction show that the transition layer retained its integrity during the plastic deformation, whereas the number fraction at peak misorientation values has risen substantially on either side of the transition layer, i.e., on the steel and aluminium layers. The pole figure maps indicate a weak texture of the AA1050 layer, but a stronger texture of the SS430 layer after warm forming than after forming at ambient temperature. The cupping experiments are performed to assess the formability of the clad and individual layers, at two different temperatures. To study the effect of each layer during forming, two possible cases of sheet placements are investigated; i.e., in the first case, the SS430 is on the outer side, and AA1050 is in contact with the punch, whereas in the second case, it is the opposite. The clad sheet shows better formability when the steel layer is on the outer side of the dome. The formability of the clad sheet is observed to increase by 15% at the warm forming temperature. The predicted simulation results are in good agreement with the experimental results. In order to investigate the effect of temperature on the residual stress, the variation of stresses was also determined and mapped on the tested samples across the dome after forming at ambient and warm temperatures. The residual stress across the dome of the tested samples after the warm forming is significantly reduced compared to that of the samples tested at room temperature. The favourable tensile properties, microstructural characteristics, and reduced residual stress at elevated temperature indicate better formability of the clad sheet with good bond integrity at warm forming temperature. [ABSTRACT FROM AUTHOR]

In single point incremental forming (SPIF), a technical challenge is to form multi feature parts, particularly those with unique structures. In response to this issue, a new process combining hydraulic bulging and SPIF is presented for the mouldless manufacture of multi-featured parts with sharp structures in a single clamping. In the first phase, hydraulic bulging is performed on the initial sheet to obtain a domed shell. In the second phase, local areas of the domed shell are subjected to SPIF with the assistance of hydraulic supports to achieve the concavo-convex features. In the third phase, the convex features are subjected to SPIF with the assistance of hydraulic bulging to achieve conical features. Simultaneously, the influence of hydraulic pressure on geometric accuracy, strain distribution, and forming mechanism is compared at different forming stages. The feasibility of the novel process can be verified through successful FEM and experiment of multi-feature parts. [ABSTRACT FROM AUTHOR]

High-strength materials are essential for applications in the structural industry. However, their limited formability restricts broader industrial use. This study proposes a novel methodology to achieve an excellent combination of formability and strength. Surface heterostructuring through laser treatment induces local austenitization on the as-rolled martensitic stainless steel. The resultant bendability was significantly improved, enabling its bending to ∼180° folding while maintaining high tensile strength. Consequently, the present surface heterostructuring suggests achieving the superior combination of strength and formability by tailoring the microstructure specifically to forming. This surface heterostructuring will explore the empty area of the formability-strength relationship.

Mg-2.2Gd-0.4Zr sheets were prepared using transverse gradient extrusion (TGE) technology to improve their formability. The effects of different TGE processes (inclination angles of the die are 15°, 30°, 37°, 45° and 49°) on the microstructure, texture, mechanical properties, and formability of extruded sheets were researched. Furthermore, the flow behaviors of Mg-2.2Gd-0.4Zr sheets during extrusion were analyzed by the finite element simulation method. For comparison, Mg-2.2Gd-0.4Zr sheets were processed by conventional extrusion (CE) process. Results showed that the texture of TGE sheets was effectively altered. With the increase of the TGE dies tilt angle, the deviation of the basal pole in the center region of the extruded sheet towards the extrusion direction (ED) increased, while in the 1/4 edge region the basal pole deviated towards the transverse direction (TD) along the ED. The multi-type textures formed in TGE sheets are mainly attributed to the extra flow velocity along the TD and the flow gradient along the ED during extrusion. High elongation of 45.6% and low yield stress of 98.9 MPa are obtained for TGE-45 sheets. In addition, the Erichsen value (IE) of the TGE-45 sheet is 5.46 mm, which is about 47% higher than the 3.72 mm of the CE Mg-2.2Gd-0.4Zr sheet. The improved formability is due to the effective coordination of multi-directional strains during the Erichsen test for the TGE sheets.

Composite metal sheets have found extensive applications thanks to their high corrosion and wear resistance, as well as greater strength, stiffness, and formability relative to the base sheets. Stainless steel composite sheets account for over 80% of the metallic composite sheets. Their higher performance and lower costs have increased their applications in the food and automotive industries. This study experimentally addressed the formability of the Al 1050/Stainless Steel 304 L bilayer sheets prepared through the cold rolling process. After designing the experiment using the response surface method, considering the layer thickness and reduction ratio of the rolling process, the bilayer sheets were prepared using the cold roll bonding process. Formability included the forming limit diagram, the magnitude of FLD0, and elongation, which were derived by Nakazima and tensile tests. Then, the formability was optimized as a function of input parameters considering the Box-Behnken method. To this end, a new criterion was presented to compare the formability of the sheets. This criterion can be used to assess the formability of a sheet considering various loading modes. Microstructural observations justified the variations in the formability of the bilayer sheets against the input parameters, i.e., thickness ratio and reduction ratio. The results indicated that the formability of the Al 1050/Stainless Steel 304 L bilayer sheet (i.e., safe forming region) reached its maximum value at tAl=4mm;tSS=0.8mm;andr=45%.

Nonwoven fabrics are used in many industries, and surface treatment by plasma can significantly change their physical and mechanical properties by changing the surface chemistry and morphology. In this paper, oxygen/argon plasma has been applied to the spunbond nonwoven fabrics to predict the obtained properties. Therefore, by using the central composite design and considering 4 independent factors including the fabric weight, fabric direction, plasma treatment duration and oxygen ratio, 51 various samples were prepared and their bending rigidity and formability were measured. SEM images showed that the surface roughness increases due to the plasma treatment. Statistical analysis revealed that all the mentioned independent factors have a significant effect on the measured parameters directly or reciprocally. Also, the use of a neural network model with two hidden layers optimized with a method according to the genetic algorithm can predict the bending rigidity and formability based on the independent factors with errors of less than 7% and 9%, respectively. The errors resulting from the surface response method for the same parameters with the same order are about 19% and 17%. The introduced method can be used as a tool to help researchers in the field of mechanical properties.

In order to enhance the formability and ridging resistance of Sn microalloyed ferritic stainless steel (FSS), an investigation was conducted on the texture and microstructure evolution, as well as formability and surface ridging of Sn microalloyed FSS at various hot rolling finishing temperatures (HRFTs). This study employed x-ray diffraction, optical microscopy, electron backscattering diffraction, tensile testing, and surface roughness measurement techniques. Hot-rolled sheets with HRFTs of 940, 870, 800, and 730 °C were subjected to annealing at 950 °C for 5 min and cold rolling at a reduction of 80%. Subsequently, they were annealed at 900 °C for 2 min. The research indicates that decreasing the HRFT has a positive impact on reducing {001} <110> grains and its texture intensity. Additionally, it leads to microstructure refinement and intensification of <111> //ND (ND: normal direction), thereby improving formability and resistance against ridging. When the HRFTs are within the range of 940–730 °C, the final sheet with an HRFT of 800 °C exhibits optimal formability and surface quality due to the formation of fine recrystallized <111> //ND grains with a sharp texture intensity. In comparison to the final sheet produced through conventional hot rolling with an HRFT of 940 °C, the average r value for the final sheet with an HRFT of 800 °C is increased by 19.4%, while the ridging height is reduced by 46.5%. This demonstrates the significance of reasonable optimization of the hot rolling process in enhancing the formability and ridging resistance of Sn microalloyed FSS. [ABSTRACT FROM AUTHOR]

Cupro–nickel alloy of 70/30 grade was experimented for its formability by SPIF tests, namely straight groove test and wall angle test using a ball attached tool, to emphasize the concern on formability and surface roughness. Two different types of ball were used, one ball was used in polished form and another one was surface-textured using Nd-Yag laser. The cupro–nickel alloy has excellent corrosion resistance and popularly used in marine environments. In this research, an attempt has been made to study the formability when using Chrome steel laser ablated ball. The results concluded that Chrome steel laser ablated ball with oil as lubrication has avoided the occurrence galling and at the same time improved the formability. When experimenting with chrome steel polished ball, the tool and sheet contact is high and the lubricating oil will be less and it is causing the sheet to get heated. The dimples on the ball's surface made by the laser retain more lubricating oil and thereby decreasing the friction which eventually leads to the delayed fracture. It is found that the formability was increased by 16% in straight groove test, 4.8% for wall angle test and surface roughness values were decreased by 1.4%. [ABSTRACT FROM AUTHOR]

High-strength materials are essential for applications in the structural industry. However, their limited formability restricts broader industrial use. This study proposes a novel methodology to achieve an excellent combination of formability and strength. Surface heterostructuring through laser treatment induces local austenitization on the as-rolled martensitic stainless steel. The resultant bendability was significantly improved, enabling its bending to ∼180° folding while maintaining high tensile strength. Consequently, the present surface heterostructuring suggests achieving the superior combination of strength and formability by tailoring the microstructure specifically to forming. This surface heterostructuring will explore the empty area of the formability-strength relationship. [ABSTRACT FROM AUTHOR]

This paper delves into the formability of material deposited by wire arc additive manufacturing. It presents a novel dieless Nakajima testing procedure that offers a practical solution for obtaining strain loading paths up to failure directly from the deposited material without the need for extracting sheet blanks. The procedure involved machining a region of the deposited material to the desired shape and thickness and using a press to drive and control the movement of a hemispherical punch. The test was designed using finite element modeling, and its effectiveness in obtaining the required strain loading paths directly from the deposited material was verified through experimentation with digital image correlation. Importantly, this novel test eliminates the need for the special-purpose tool setup required in conventional Nakajima sheet formability tests, thereby simplifying the overall testing process. [ABSTRACT FROM AUTHOR]

Concurrently improving the formability and post-formed strength of Al-Zn-Mg alloy sheets is crucial for producing high-strength parts with complex shapes. A novel process of aging warm-forming (AWF) to form solution heat-treated and water-quenched aluminum alloy sheets is proposed in this paper. The as-quenched AA 7075 sheet was first pre-aged and then formed at the desired temperature. The automotive paint–bake process was then utilized as the second aging step to achieve the target strength of the formed part. Additionally, the post-formed strength and warm formability of specimens under the AWF process conditions, as well as the warm-forming of various heat-treated Al-Zn-Mg alloy sheets proposed in previous studies, were compared through tensile and limit dome height tests. Precipitate characteristics of specimens subjected to different warm-forming process conditions were examined to understand their impact on warm formability. The warm formability of Al-Zn-Mg alloy sheets was significantly enhanced, and the post-formed strength achieved was more than 90% of the strength of as-received AA 7075-T6 sheets under the AWF process condition. The results demonstrated the feasibility of this novel AWF process to manufacture Al-Zn-Mg alloy stamped parts for improved spring-back, formability, and good overall post-formed strength. The results also indicate that microstructural characteristics in Al-Zn-Mg alloy sheets under different warm-forming process conditions have a noticeable influence on warm formability and final mechanical properties. [ABSTRACT FROM AUTHOR]

Sheet metal formation plays a cost-effective and significant role in the fabrication of automobile components. Typically, a forming limit diagram (FLD) is used to determine the strain limit of the material fracture during hot forming. In this study, the Erichsen cupping test is conducted on an Al(7075) sheet at 300, 350, 400, and 450 °C to determine the FLD. The results demonstrate the displacement increases with increasing temperature and load, and it is decreased at 450 °C. Finite element analysis (FEA) of the Erichsen cupping test of the Al sheet is performed with the damage theory using ABAQUS software, and the results are compared with the experimental results. To minimize errors in the Finite Element Analysis (FEA), simulations were conducted by applying the fracture energy value ( G f ). It was observed that the displacement increased in the load–displacement curve as the fracture energy value ( G f ) increased at all temperature values. Additionally, as the G f value increased with temperature, the energy absorption capacity until fracture also increased. [ABSTRACT FROM AUTHOR]

In recent years, significant attention has been garnered by Tailor Rolled Blanks (TRBs), especially within the automotive industry, attributed to their unique performance characteristics, defined by varying thickness profiles. Nonetheless, the inherent structural complexities of TRBs have led to non-uniform deformation during forming processes, thereby compromising elongation and formability. In this study, an exploration into the deformation of TRBs under uniaxial tensile conditions is elucidated, centering specifically on TRBs transitioning from a thickness of 1–2 mm over a 100 mm span. An assessment of the properties of TRBs following partial annealing is conducted, and mechanisms responsible for thickness variations and the revelation of intrinsic mechanical traits are identified through microstructural examinations. Exploration of the mechanical behavior of TRBs under tension is undertaken, and a methodological approach for optimizing the distribution of mechanical properties is proposed. Validation is achieved through the employment of finite element models, showcasing a performance improvement in the optimized TRBs, with uniform elongation rates surpassing those of non-optimized TRBs by up to 197%. Moreover, an outperformance of uniform-thickness materials by up to 51% is exhibited by the optimized TRBs. These insights are anticipated to bolster the application and efficiency of TRBs across various engineering sectors, aligning coherently with the intelligent design and advanced materials implications within the realm of mechanics and materials in design, as spotlighted by "The International Journal of Mechanics and Materials in Design". This exploration intricately intertwines mechanics, material engineering, and intelligent design, offering a comprehensive view that stands to fortify the symbiotic relationship between advanced materials and the design process. [ABSTRACT FROM AUTHOR]

Heat-assisted Incremental Sheet Forming (HA-ISF) is a viable forming technique that uses the heat-source to form the sheet materials incrementally and progressively. The hard-to-form sheet materials may be formed effectively using the HA-ISF method which are otherwise difficult to form at the room temperature. HA-ISF may enable the greater formability of the formed sheet-parts and reduce the required forming forces for fabricating the sheet components. These possibilities have motivated the researchers to explore various aspects of HA-ISF and the effects of process factors on the various outcomes. In this review article, various dimensions and methods of this emerging technique of sheet forming have been explored. Each method of HA-ISF has been studied against the hard-to-form materials to establish a trend on the outcome like forming force, surface roughness and formability. The capabilities of these methods of warm forming have also been discussed for the hard sheet materials along with the mechanisms of the obtained results. Results shows that the nature of materials and the mode of heating the sheet during the forming process can affect the formability, surface roughness and the required deforming loads effectively. An attempt has also been made by the authors for providing and establishing the criteria to estimate the deforming loads that are required to deform the sheet material by using the analytical and predictive modelling approach. Available analytical models show difficulty in the prediction of the input parameters for desired output parameters. While the development of numerical models is very time-consuming and has significant deviation in result for the upper range of input parameters due to variation in material properties with varying temperature. Whereas, empirical modelling can be a viable approach to predict the HA-ISF process. In addition, various applications of the HA-ISF have also been discussed for streamlining this novel technique for industries to produce customized products from hard-to-form materials. Results also shows that the HA-ISF process is efficient for increasing the formability of hard sheet materials and for reducing the required deforming loads. Achieving the better dimensional accuracy and good surface finish is still the challenge in HA-ISF and researchers may focus on these areas for enhancing the capability of this technique of warm forming. [ABSTRACT FROM AUTHOR]

This research develops and validates a low-cost, simple hydraulic bulge test device designed to characterize the formability of thin metal foils under pure biaxial strain conditions. The study focuses on yellow brass foil (Cu-Zn) with a thickness of 0.2 mm, using a device with a small bulge diameter (20 mm), relevant for mini-forming applications. The collected data includes the relationship between pressure and bulge height, which is then converted into effective stress and effective strain. This device aims to directly generate stress-strain data for calculating the strain hardening exponent (n-value). Key innovations include the use of a small bulge diameter suitable for mini-forming and the application of circular markers on the specimen surface to facilitate the conversion of pressure-height data into stress-strain parameters. Validation results show that the device accurately measures the pressure vs. bulge height relationship. While initial data demonstrates accuracy in measuring pressure and bulge height, additional methods are required to directly convert these measurements into effective stress and strain parameters.This research provides an economical solution for material characterization in mini-forming applications and presents a reliable tool for further studies on various types of thin metal foils. [ABSTRACT FROM AUTHOR]

Origami patterns play a critical role in the field of soft and reconfigurable robotics. The revolved body formed by waterbomb units is also widely used in robot design. The kinematic model plays a key role in understanding motion characteristics and is vital for dynamic modeling and control of robots based on origami. However, while the deformation of origami patterns is well-studied on the finite element level, the assembly of rigid origami patterns is rarely explored on the kinematic level. Therefore, we propose a chain-like assembly method for constructing revolved bodies using rigid waterbomb units, ensuring crease status unalternation, collision avoidance, axis existence, and seamless assembly. We explore the formability of waterbomb units and investigate the resulting revolved body with some layer and column numbers of waterbomb units. Results demonstrate that increasing the number of columns does not necessarily provide more space for building layers. Additionally, they reveal boundaries of the layer and column numbers for constructing the revolved body and highlight the impact of the aspect ratio and configuration of the waterbomb units on the formability of the revolved body. This method can provide insights for origami-based robot research and can be extended to model other origami patterns. [ABSTRACT FROM AUTHOR]

A positioning grid is a key clamping structure for fixing the transverse and axial positions of fuel assemblies in nuclear reactors, and it is generally prepared by the transverse stamping of a Zr-4 sheet. However, the texture formed in the processing process of Zr-4 sheets can affect formability, resulting in cracking in the stamping process. Therefore, the relationship between the formability of Zr-4 sheets and the normal Kearns factor (Fn) of basal texture was studied in this paper. The results showed that the Zr-4 sheet with an Fn equaling 0.720, prepared by an isobaric reduction rolling process, would crack in the stamping process. To avoid the cracking during stamping, the formability improvement of Zr-4 sheets based on texture optimization was discussed. By using the finite element model (FEM) and a visco plastic self-consistent (VPSC) model coupled simulation, the relationship between the initial textures and formabilities of Zr-4 sheet is established. It is found that the hardening exponents (n) decreased with increasing Fns in VPSC simulations. Meanwhile, as the Fn increases, cracks are prone to occur at the bottom corner of the stamped sheet in finite element simulation. Given the results from FEM and VPSC simulations, it is proposed that the Fn should be controlled to be less than 0.7 for preventing cracks in the sheet during stamping. Additionally, a new rolling process named non-isobaric reduction rolling was designed in which the Fn of the Zr-4 sheet is successfully reduced to 0.690. The stamping results indicate that the sheet is free of cracks under an Fn of 0.690. Therefore, texture optimization with the proposed rolling process can improve the formability of Zr-4 sheets, which effectively solves the cracking problem of Zr-4 sheets. [ABSTRACT FROM AUTHOR]

This paper is focused on improving material formability in hybrid wire-arc additive manufacturing comprising metal forming stages to produce small-to-medium batches of customized parts. The methodology involves fabricating wire arc additive manufactured AISI 316L stainless steel parts subjected to mechanical and thermal processing (MTP), followed by microhardness measurements, tensile testing with digital image correlation, as well as microstructure and microscopic observations. Results show that mechanical processing by pre-straining followed by thermal processing by annealing can reduce material hardness and strength, increase ductility, and eliminate anisotropy by recrystallizing the as-built dendritic-based columnar grain microstructure into an equiaxed grain microstructure. [ABSTRACT FROM AUTHOR]

In this study, the compositional design of high-formability, high-bake-hardening Al–Mg–Zn-Cu-based aluminum alloys was carried out, and process conditions were established to secure mechanical properties under harsh conditions for Al–Mg–Zn-Cu-based alloys. Using JMatPro13.0 for precipitation phase simulation, the optimal pre-aging temperature and time of the design composition were selected. Through the introduction of pre-aging, it was confirmed that no over-aging phenomena occurred, even after bake-hardening, and it was confirmed that it could have mechanical properties similar to those of test specimens subjected to traditional heat treatment. Through DSC (Differential Scanning Calorimetry) and TEM (Transmission Electron Microscope) analyses, it was found that pre-aging provided sufficient thermal stability to the GP (Guinier–Preston) zone and facilitated transformation to the η'-phase. In addition, it was confirmed that, even under bake-hardening conditions, coarsening of the precipitation phase was prevented and number density was increased, thereby contributing to improvements in the mechanical properties. The designed alloy plate was evaluated as having excellent anisotropy properties through n-value and r ¯ -value calculations, and it was confirmed that a similar level of formability was secured through FLC (Forming Limit Curve) comparison with commercial plates. [ABSTRACT FROM AUTHOR]