The dependence of α-phase size on flow stress was characterized by a proposed kinetic model during dynamic recrystallization （DRX） steady state in Ti60 alloy. Accord- ing to the isothermal compression tests, the influence of deformation parameters on the steady-state flow stress was analyzed and the constitutive equation was established to predict the steady-state flow stress under different defor- mation temperatures and strain rates. A power-law rela- tionship between the DRX average grain size and steady- state flow stress with an exponent of -2 is obtained from the dynamic balance during DRX steady state. The effect of deformation parameters on at-phase size was observed through the microstructure after deformation, and the applicability of the model for Ti60 alloy was verified by the comparison between predicted and experimental data.
hui lizhang-long zhaohong-zhen guoyong-quan ningze-kun yaokai li
Microstructure and tensile properties of TC21 titanium alloy after near-isothermal forging with different parameters plus solution treatment and aging were investigated. It is found that the residual β matrix, which was strengthened by fine secondary α platelets forming during aging, exists in all the samples; while primary equiaxed α phase, bent lamellar α phase and α plates are simultaneously or individually present in one sample. The strength of alloy increases proportionally with increasing the content of residual β matrix, which is the result of increasing α/β interphase boundary. The plasticity of alloy has a downward trend as the content of residual β matrix increases. This attributes to the increase of fine secondary α platelets, which are cut by dislocations during the deformation. Additionally, coarse α plates with long axis parallel to the maximum resolved shear stress（MRSS） also reduce the plasticity of TC21 alloy.
