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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.

Hot deformation behaviors and microstructure evolution of Ti−3Al−5Mo−4Cr−2Zr−1Fe (Ti-35421) alloy in the βsingle field are investigated by isothermal compression tests on a Gleeble−3500 simulator at temperatures of 820−900 °C and strain rates of 0.001−1 s−1. The research results show that discontinuous yield phenomenon and rheological softening are affected by the strain rates and deformation temperatures. The critical conditions for dynamic recrystallization and kinetic model of Ti-35421 alloy are determined, and the Arrhenius constitutive model is constructed. The rheological behaviors of Ti-35421 alloys above βphase transformation temperature are predicted by the constitutive model accurately. The EBSD analysis proves that the deformation softening is controlled by dynamic recovery and dynamic recrystallization. In addition, continuous dynamic recrystallization is determined during hot deformation, and the calculation model for recrystallization grain sizes is established. Good linear dependency between the experimental and simulated values of recrystallized grain sizes indicates that the present model can be used for the prediction of recrystallized grain size with high accuracy.

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)Cxphase 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)Cxwas revealed by high-resolution transmission electron microscopy (HRTEM) and energy-dispersive spectroscopy (EDS). In the water-quenched WC–30Co–VC, (W,V)Cxprecipitates were found as thin layers at the WC/Co interfaces. In contrast, both thin layers of similar thickness and nanoparticles of (W,V)Cxwere observed in the furnace-cooled counterpart. These observations listed above suggested that thin (W,V)Cxlayers were stable structures effectively suppressing the growth of WC grains and their thickness remained independent of the cooling rate. The (W,V)Cxnanoparticles, however, may be inhibited through rapid cooling, ensuring the VC-doped WC–Co cemented carbides desired toughness.