Static Globularization and Grain Growth Behavior of Ti-5Al-2Sn-2Zr-4Cr-4Mo(Ti-17) Alloy Under Static Heat Treatment Process

Grain growth behavior and static globularization behavior of the Ti.-5Al-2Sn-2Zr-4Cr-4Mo(Ti-17) alloy (with the lamellar starting microstructure and the equiaxed-grained-microstructure) under static heat treatment process were investigated in this work. Rapid grain-growth and static globurarization are exhibited in the 1123HR specimen (with the equiaxed starting microstructure) rather than the lamellar specimen, which is mainly due to the quite difference in fraction of Burgers orientation relationship (BOR) (with coherent relationship) between alpha and beta phases. The interface energy of gamma(alpha beta) at BOR was estimated to be approximately 0.01 J/m(2) according to Lifshitz-Slyozov-Wagner(LSW) model. Static globularization behavior of the 1123HR specimen is reasonably explained in relation to the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model. Here, similar apparent activation energies were exhibited for both behaviors of grain growth and globularization, indicating the similar rate-limiting mechanism for both these behaviors.