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The effect of cold rolling and annealing on the microstructure and properties of an Fe–13Cr–4.5Al–2.2Mo–1.1Nb alloy was investigated. The results showed that the recrystallization rate increased with increasing annealing temperature and rolling reduction. Recrystallization kinetics was constructed based on Johnson–Mehl–Avrami–Kolmogorov equation. The apparent activation energies of recrystallization were 161.385, 144.770, and 95.362 kJ/mol for the samples with 30%, 50%, and 70% cold-rolling reduction, respectively. With the cold-rolling reduction increasing, the texture γ fiber partly changed to 〈100〉//ND. After annealing, γ fiber of the alloy with 30% thickness reduction retained, the subgrains disappeared through merging, and the proportion of coincident site lattice grain boundaries increased and became more continuous. 30% cold-rolling reduction alloy annealed at 730 °C for 120 min not only possessed relatively high yield strength (YS) of ~ 730 MPa and ultimate tensile strength (UTS) of ~ 880 MPa, but also exhibited elongation of ~ 16% at room temperature. After annealing at 730 °C for 120 min, 70% cold-rolled alloy has finer and more uniform grain, with higher elongation of ~ 22%, YS of ~ 615 MPa and UTS of ~ 774 MPa. The mechanism of mechanical properties difference was explained according to Schmid factor analysis. These results provided an effective way for tuning strength and ductility of FeCrAl alloy.

In this paper, the Widmanstatten microstructure in an extruded near-α titanium alloy (Ti-5.5Al-2Zr-1Mo-2.5V) pipe was changed effectively by solid solution treatment at 920 °C for 2 h. The treatment produced intermittent lamellar α and discontinuous α grain boundaries (αGB), and aging at 450 °C for 2 h introduced a high density of nanosized secondary α (αs). The microstructure consisted of the lamellar α, αGB and transformed β demonstrated a good combination of yield strength 1064 MPa and elongation 10.5%. Severe plastic deformation occurred inside the lamellar α during the tensile process, resulting in high-density dislocation tangles and dislocation cells. Furthermore, the stretching imposed on the tensile sample before aging generated dislocations, which piled up near the α/β interface. Thus, a coordinated deformation between lamellar α and transformed β, and the resultant strain partition contributed to an improvement in the ductility. Moreover, dislocation motion was effectively obstructed near the α/β interfaces, which dramatically strengthened the alloy. A solid solution at a middle temperature in the α + β region and aging at a low temperature provided an effective way to improve the strength and ductility simultaneously in titanium alloys with Widmanstatten microstructure.

Composites of graphene nanoplatelets (GNPs) and 8030 aluminum alloy powder were prepared using powder modification + semisolid extrusion processes. The density, electrical conductivity, mechanical properties and microstructure of the specimens were investigated. The results show that the composites with 0.5 wt% GNPs achieved an enhancement in yield strength (37.5%) and ultimate tensile strength (62.9%), while its elongation and electrical conductivity were comparable, as compared with the 8030 aluminum alloy without GNPs prepared by the same process. Furthermore, the related strengthening mechanism of the composites with GNPs directional distribution was discussed.

In this study, 0.2 wt% zirconium (Zr) added Sn–1.0Ag–0.5Cu (SAC105) lead-free solder alloy was prepared and its microstructure, tensile property, and aging stability were investigated and compared with the original SAC105 solder alloy. The SAC105 and SAC105-0.2Zr solder alloys were fabricated by vacuum induction melting method. The results showed that the Zr-added SAC105 solder exhibited a significantly refined microstructure. The primary β-Sn phases, Ag3Sn particle size, and spacing of Ag3Sn had been obviously reduced with the addition of trace amounts of Zr. The tensile test demonstrated that both strength and elongation of the SAC105-0.2Zr solder improved because of the finer microstructure. Isothermal aging was performed at 180 °C for 36 h, 84 h, and 156 h. The existence of Zr could significantly inhibit the coarsening of the Ag3Sn phases, thus enhancing the microstructure stability under severe aging conditions. Moreover, the Zr-added SAC105 solder showed significant decrease in supercooling, but the melting range was almost unchanged.

Ni-based self-lubricating composites containing a fixed amount of hexagonal boron nitride (h-BN) (5 wt%) and different amounts of graphene (0–1.5 wt%) were prepared by ultrasonic dispersion, high-energy ball milling, and spark plasma sintering. The effects of the graphene content on the physical, mechanical, and wear properties of the Ni/h-BN composites were evaluated. These properties were first enhanced with increasing graphene content, reaching optimal behavior for a graphene content of 1 wt%, and then degraded with further graphene addition. Compared to the pure Ni/h-BN composite, the relative density, hardness, and bending strength of the composite with 1 wt% graphene increased by 2.7%, 7.4%, and 6.3%, respectively, while the friction coefficient decreased by 56% to 0.31, and a reduction in wear rate by a factor of 5–15 was observed. The mechanism for improving the wear properties of the composite with added graphene was due to the formation of a graphene lubricating film on the worn surface, which increased the load bearing capacity of the surface and enhanced lubrication during wear.

Industrial application of superhydrophobic surfaces is often hindered by complicated process and sophisticated machines. A facile wet etching method (sandblast, HCl and sandblast/HCl) with vapor deposition of PFDS (1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane) was applied to fabricate superhydrophobic surface of heat-resistant steel used for vane. The coating component, surface morphology and surface roughness parameters of sample were observed by attenuated total reflectance Fourier transform infrared spectroscopy, scanning electron microscopy and atomic force microscopy. Static water contact angle (WCA) of samples with and without PFDS coating was measured by contact angle goniometer. The results showed that WCA values of polished, sandblast, HCl and sandblast/HCl-etched samples are 98°, 97°, 100° and 101°, respectively, and increase to 112°, 148°, 151° and 154° after vapor deposition of PFDS. The sandblast/HCl-etched sample with PFDS coating shows higher superhydrophobicity because of very large surface roughness and lotus protrusion-like structure. The superhydrophobicity of this fabricated surface has no obvious change after 38 cycles of the film adhesion test, indicating excellent durability.

High-temperature plane-strain compression of a Ti-6Al-2Sn-4Zr-2Mo (Ti-6242) alloy with a lamellar structure was applied by a thermal simulation machine Gleeble 3800 at a temperature of 1223-1370 K and a strain rate of 0.01-10 s−1. Constitutive relations between the flow stress and strain at different temperatures and strain rates were constructed based on the Arrhenius equation. Processing maps based on the dynamic material model at strains of 0.5, 1.0, and 1.25 were also constructed to analyze the mechanism and instability of high-temperature deformation. Dynamic recrystallization was found to occur at 1223-1313 K and 0.01-0.1 s−1, with a peak efficiency of power dissipation of 70%. Observations of the microstructure demonstrated that α platelets and dynamic globularization were responsible for dynamic softening in the α + β phase field. Flow instability behaviors occurred at 1263-1343 K/1.78-10 s−1, 1233-1283 K/0.1-3.16 s−1, and 1353-1373 K/0.56-1.78 s−1, and adiabatic shear bands and microcracks were observed in these domains. Thus, for the lamellar Ti-6242 alloy, the recommended hot rolling parameters were 1243-1333 K and 0.01-0.1 s−1. Electron backscattered diffraction results revealed that the dynamic restoration mechanism in the β phase field was dynamic recovery when the strain rate was as high as 10 s−1.

In this paper, LiNiPO4 powders were prepared by sol gel method using citric acid as chelating agent. The article investigated the effect of annealing temperature and citric acid: Li molar ratio (cit/Li) on the structure and electrochemical properties of LiNiPO4 material. The results indicated that pure Pnma LiNiPO4 phase was synthesized at 700 and 800 °C. It was found that the increase of annealing temperature and cit/Li induced rod-to-sphere transition. The particles sizes increased with increasing annealing temperature, while the particles sizes were increasing firstly and then decreasing with increasing the ratio of cit/Li. Decreasing particles sizes had an advantage of both decreasing the charge transfer resistance (Rct) and improving the reversible capacity of pure olivine LiNiPO4 samples. Spherical particles (100–200 nm) prepared at 700 °C with cit/Li molar ratio of 2:1 were found to have low resistance, high electrochemical reversibility, cycle stability.

The microstructures and mechanical properties of powder metallurgy Inconel 718 alloy were investigated in the temperatures range between 25 and − 253 °C. Tensile strength increased with the decrease in temperature, while the ductility first increased and then decreased. There was no significant change in impact toughness. When the temperature was − 253 °C, a zigzag stress–strain curve was observed for the alloy, owing to the interaction of dislocation glide and twinning, which effectively maintained the relatively good ductility.

Fatigue crack growth as a function of a phase volume fraction in Ti-6Al-2Sn-4Zr-2Mo (Ti-6242) alloy was investigated using fatigue testing, optical microscopy, scanning electron microscopy, and transmission electron microscopy. The α + β annealing treatments with different solid solution temperatures and cooling rates were conducted in order to tailor microstructure with different a phase features in the Ti-6242 alloy, and fatigue crack growth mechanism was discussed after detailed microstructure characterization. The results showed that fatigue crack growth rate of Ti-6242 alloy decreased with the decrease in volume fraction of the primary a phase (αp). Samples with a large-sized α grain micro-structure treated at high solid solution temperature and slow cooling rate have lower fatigue crack growth rate. The appearance of secondary a phase (αs) with the increase of solid solution temperature led to crack deflection. Moreover, a fatigue crack growth transition phenomenon was observed in the Paris regime of Ti-6242 alloy with 29.8% αp (typical bi-modal microstructure) and large-sized a grain microstructure, owing to the change of fatigue crack growth mechanism.

The influence of ZnO nanowires on the interfacial micro-mechanical behavior of carbon fiber/epoxy microdroplet structures was studied using micro-Raman spectroscopy. Carbon fibers were modified by adding ZnO nanowires to the surface to improve interfacial bonding strength, using a hydrothermal method. The distributions of axial stress, shear stress, and stress transfer efficiency in the epoxy microdroplet were then measured. The results show that samples containing carbon fiber coated with ZnO nanowires had lower axial stress and larger interfacial shear stress than those with unmodified carbon fiber under the same strain. Specifically, under a 0.25% applied strain, carbon fiber coated with ZnO nanowires showed increased maximum values of shear stress from 6.21 to 22.80 MPa, with maximum values of stress transfer efficiency increasing from 1.07 to 6.88%. Under increased strain, the stress transfer efficiency decreased due to the fracture of ZnO nanowires. Two possible types of ZnO nanowire fracture modes are discussed, and a model of microstress transfer is introduced.

The grain growth retardation mechanism and the effect of cooling rate on VC-doped WC–Co cemented carbides were investigated in this work. WC–30Co and WC–30Co–VC were prepared by powder metallurgy, liquid-phase sintering at 1400 °C and followed by water quenching (>150 °C/s) or furnace cooling (~0.083 °C/s). Based on the results of electron probe microanalysis (EPMA), we found that WC concentration in the Co binder was independent of VC doping during liquid-phase sintering, hence barely contributing to the retardation of WC grain growth. In contrast, the (W,V)C x phase formed at the WC/Co interfaces played a major role in retarding WC grain growth during liquid-phase sintering. The effect of cooling rate on the morphology of (W,V)C x was revealed by high-resolution transmission electron microscopy (HRTEM) and energy-dispersive spectroscopy (EDS). In the water-quenched WC–30Co–VC, (W,V)C x precipitates were found as thin layers at the WC/Co interfaces. In contrast, both thin layers of similar thickness and nanoparticles of (W,V)C x were observed in the furnace-cooled counterpart. These observations listed above suggested that thin (W,V)C x layers were stable structures effectively suppressing the growth of WC grains and their thickness remained independent of the cooling rate. The (W,V)C x nanoparticles, however, may be inhibited through rapid cooling, ensuring the VC-doped WC–Co cemented carbides desired toughness.

2524-T3 aluminum alloy sheets with different grain sizes (13 μm, 59 μm, 178 μm, 355 μm, 126 μm, and 87 μm) were prepared using methods such as rolling and annealing. The microstructures and mechanical properties of the 2524-T3 aluminum alloy sheets were studied using optical microscopy (OM), scanning electron microscopy (SEM), and tensile and fatigue crack growth (FCG) rate tests. The grain size had a significant effect on the fatigue crack growth (FCG) rate. Alloys with grain sizes between 50 and 100 μm exhibited high fatigue crack propagation resistances and the lowest FCG rates ( da/dN = 1.05–1.45 × 10 −3 mm/cycle at ΔK = 30 MPa m 1/2 ). Microstructural observations revealed that fatigue cracks propagated more tortuously in the alloy with grain sizes within the range of 50–100 μm. This result is attributed to the combined effects of grain boundaries, crack deflection, fracture surface roughness-induced crack closure, and plasticity-induced crack closure.

We present a combined experimental and theoretical study on interfacial structure and thermodynamics in internally oxidized Ag(SnO2)p composites. The orientation relation between in situ formed SnO2 particles and the silver matrix was characterized using high-resolution transmission electron microscopy techniques. First-principles energetic calculations were then performed to predict the equilibrium interface structures and corresponding adhesion properties as functions of temperature and oxygen partial pressure. All results were combined to construct the interface-level thermodynamic stability diagram, for guiding the optimal design of internal oxidation parameters.

Black carbon-stabilized anatase particles were prepared by a simple one-step hydrothermal–electrochemical method using glucose and titanium citrate as the carbon and titanium source, respectively. Morphological, chemical, structural, and electrochemical characterizations of these powders were carried out by Raman spectroscopy, Fourier-transform infrared spectroscopy, x-ray diffraction, scanning electron microscopy, and cyclic voltammetry. It was revealed that 200-nm carbon/anatase TiO2 was homogeneously dispersed, and the powders exhibited excellent cyclic performance at high current rates of 0.05 V/s. The powders are interesting potential materials that could be used as anodes for lithium-ion batteries.

We report a first-principles study for assessing the roles of rare-earth (RE) dopants (Y and Ce) on adhesion of the thermally grown α-Al2O3/γ-Ni(Al) interface. The effects on adhesion of temperature, stoichiometry, Al chemical activity, and Y/Ce segregation are thoroughly examined, and the results are compared with those of impurity S. A major discovery is that very similar to (perhaps more efficiently than) Hf, doping with Y provides several concurrent benefits, including increasing the adhesion of the weak stoichiometric interface by a factor of ~3. Doping with Ce almost doubles the adhesion of the stoichiometric interface, but it may reduce the adhesion of the strong Al-rich interface by ~20 %. Also, notably, Ce has a very strong capability of gettering detrimental S in Ni, which is almost triple those of Y and Hf.

θ″-phase, with a formal stoichiometry of Al3Cu, is a coherent, metastable precipitate (GP-II) phase commonly found in Al-based aerospace alloys. In this paper, we employed a first-principles based method to study the energetics of the Al/θ″ interface as response to external strains. The potential effects of temperature, Cu activity, and different strain modes on interface energy (γ Al/θ″) were systematically investigated. Calculations show that (i) an unstrained γ Al/θ″ always increases with temperature: as temperature increases from T = 298 to 498 K, γ Al/θ″ increases by ~9.0 %; (ii) γ Al/θ″ is more sensitive to compressive strains than to tensile strains of the same magnitude. In particular, for a parallel compressive strain increasing from 0 to 2 % at a typical aging temperature, γ Al/θ″ decreases by ~6.6 %, while a vertical compressive strain of 2 % has a slightly stronger impact by decreasing γ Al/θ″ by ~9.6 %. Different influences of applied strain/stress on the formation energies of different orientated interfaces can be further exaggerated by the Poisson effect, and eventually affect the preferential precipitation orientation of θ″ in the matrix.

Black carbon-stabilized anatase particles were prepared by a simple one-step hydrothermal–electrochemical method using glucose and titanium citrate as the carbon and titanium source, respectively. Morphological, chemical, structural, and electrochemical characterizations of these powders were carried out by Raman spectroscopy, Fourier-transform infrared spectroscopy, x-ray diffraction, scanning electron microscopy, and cyclic voltammetry. It was revealed that 200-nm carbon/anatase TiO2 was homogeneously dispersed, and the powders exhibited excellent cyclic performance at high current rates of 0.05 V/s. The powders are interesting potential materials that could be used as anodes for lithium-ion batteries.

The recent increasing interest of T-phase in Al alloy has been switched to its twins. In this study, we employed high resolution transmission electron microscopy to study and compare the morphology and orientation relationships (OR) of T-phase and its twins in an Al–Cu–Mg–Mn alloy. It is found that T-phase tends to form on the {403}Al habit planes and exhibit a rod-like shape, with it longitudinal axis, [010]T, being parallel to the matrix [010]Al direction. Three different OR types are determined between T-phase and Al matrix, namely, {200}T〈010〉T//{200}Al〈010〉Al (OR-I), {200}T〈010〉T//\( \{ 40\bar{3}\}_{\text{Al}} \)〈010〉Al (OR-II), and {200}T〈010〉T//{301}Al〈010〉Al (OR-III). OR-II is the most widely observed OR, while OR-I and III can form from the OR-II by twinning. During the twinning, the cross-section of T-phase transforms from a parallelogram-like shape into a shell-like shape. Further analyses on the shell-like T-twins strongly suggest that tenfold twins could form directly from the successive twinning of an individual T crystal.

The 8% (mass fraction) yttrium-partially-stabilized zirconia (8YSZ) ceramic was fabricated via liquid phase sintering at 1 200–1 400 °C by adding different mass ratios of CuO-16.7%TiO2 (molar fraction) as sintering aid. Relative density, microstructure, Vickers hardness and bending strength as a function of sintering temperature and additive content were investigated. The experiment results show that liquid phase sintering at low temperature can be realized through adding CuO-16.7% TiO2 to 8YSZ. The Vickers hardness and bending strength of samples with sintering aid are generally much higher than those of samples without sintering aid for all sintering temperatures, and increase with the increase of sintering temperature. When the addition content of CuO-16.7% TiO2 is beyond 0.5%, the relative density, Vickers hardness and bending strength decrease with the increase of the mass ratio of sintering aid. Low additions of sintering aid are beneficial to aiding densification; high additions of sintering aid are detrimental to the sintered properties mainly due to greater amounts of pores generated by the volatilization of oxygen with the eutectic reaction between copper oxide and titanium dioxide. It is found that the fine grain size and high relative density are two main reasons of the high bending strength and Vickers hardness of the materials.

The tensile deformation behavior of extruded samples of Mg-0.8 pct Gd and Mg-0.8 pct Gd-0.5 pct Mn-0.45 pct Sc (at. pct) alloys has been studied. Both alloys exhibit serrated flow when they are tensile tested at temperatures ranging from 150 °C to 300 °C and at strain rates of 1.67 × 10−4 s−1 to 1.67 × 10−2 s−1, and this serrated flow behavior is significantly affected by postextrusion heat treatments. Combined with observations made by transmission electron microscopy (TEM) and three-dimensional atom probe (3DAP), the serrated flow is attributed to dynamic interactions between solute atoms and gliding dislocations. It is suggested that Gd atoms in the solid solution matrix of magnesium are mainly responsible for the serrations in the two alloys. The additions of Mn and Sc to the Mg-Gd alloy strengthen the dynamic solute-dislocation interactions and lead to a lower critical strain and larger stress drops of the serrated flow in the Mg-Gd-Mn-Sc alloy.

The gas atomized Ag-9.26wt%Sn-0.44wt%La alloy powders were oxidized in air between 400 and 900 °C. The oxidation thermodynamics, kinetics and microstructure of the alloy were investigated. We suggested that the addition of La may accelerate oxidation of Sn and prevent the formation of the dense SnO2 film. The suitable oxidation temperature of the alloy powders is 800 °C in air. After internal oxidation, many cracks were observed on the surface of the alloy powders. In addition, the whole oxidation process of the alloy powders is controlled by the oxygen diffusion. The diffusion coefficient of oxygen in the alloy powders at 800 °C is about 1.5 times larger than that at 700 °C on the initial stage of internal oxidation, while that is 4.5 times on the subsequent stage.

An attempt was made to explore the possibility of fabricating AA2618 reinforced by submicron AIN particles. The results show that the addition of AIN particles decreases remarkably the grain size of the alloy. The 2618-AIN dispersion-strengthened alloy has the same strength as AA2618 at room temperature in the T6 state, but exhibits significantly higher strength after isothermal exposure at 200 °C for 100 h. The strength of the dispersion-strengthened alloy at elevated temperatures was greater than that of AA2618.

Niobium suboxide powder was pressed and sintered in vacuum into NbO electrolytic capacitor sintered anode. High voltage and constant current formation experiment was performed on NbO electrolytic capacitor anode, during which electrolyte was 0.01% H3PO4 solution, temperature was 90 °C and current was 50 mA per gram sample. Through the relationship between anode voltage and time and scanning electron microscopy(SEM) images of invalidated anode and normal forming anode, invalidation manner and mechanism of NbO electrolytic capacitor anode were discussed. The results show that, the main invalidation manner of NbO electrolytic capacitor anode is not short circuit but open circuit, which is different to that of traditional Ta electrolytic capacitor anode. The reason of invalidation is that anode oxide film whose thickness increases gradually penetrates the “connection neck’ among anode powder particles, which leads to the open circuit invalidation of anode. Compared with Ta electrolytic capacitor, NbO electrolytic capacitor has better security.

The Gibbs free energy was calculated between phosphorus and the main elements in Al-Si-Cu alloys sampled as A390 to study the reaction process and give theoretical directions for the adding of phosphorus in industry. The results show that the elements such as aluminum, silicon, and copper have the capabilities to react with phosphorus according to the preference of Al, Cu, Si. As temperature increases, the reactions between phosphorus and the elements become more difficult. If aluminum is in existence, the phosphides of other elements will transform to aluminum phosphide.

Ternary alloying of MoSi2 with adding a series of transition elements was investigated by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS). Iron, Co, Ni, Cr, V, Ti, and Nb were chosen as alloying elements according to the AB2 structure map or the atomic size factor. The studied MoSi2 base alloys were prepared by the arc melting process from high-purity metals. The EDS analysis showed that Fe, Co, and Ni have no solid solubility in as-cast MoSi2, while Cr, V, Ti, and Nb exhibit limited solid solubilities, which were determined to be 1.4±0.7, 1.4±0.4, 0.4±0.1, and 0.8±0.1. Micro-structural characterization indicated that Mo-Si-MVIII (MVIII=Fe, Co, Ni) and Mo-Si-Cr alloys have a two-phase as-cast microstructure, i.e., MoSi2 matrix and the second-phase FeSi2, CoSi, NiSi2, and CrSi2, respectively. In as-cast Mo-Si-V, Mo-Si-Ti, and Mo-Si-Nb alloys, besides MoSi2 and C40 phases, the third phases were observed, which have been identified to be (Mo, V)5Si3, TiSi2, and (Mo, Nb)5Si3.