Abstract
The effects of heating rate on the alloy element partitioning and mechanical properties during the phase transformation of α-→β in Ti-6Al-4 V alloy under solution treatment have been investigated by the ex-periments and phase field simulations,which reveal the evolutions of microstructure and compositions at the non-equilibrium state and well verify the experimental results.The specific results indicate that the compositions measured through electron probe micro-analysis (EPMA) under a lower heating rate are close to the equilibrium ones corresponding to the solution temperature.Heating up to the target solution temperature,as the heating rate increases,the Al content decreases and V increases in the pri-mary α (αp) grain with a larger size,the volume fraction of αp increases and the composition gradient between αp and β phases gets steeper.The interrelated relationship among the diffusion,compositions,solution temperature and free energy of the system has been discussed in detail.Moreover,increasing the heating rate (～20.0 K/min) may help to improve the mechanical properties of the alloy by mainly adjusting the αp/βt volume fractions,αp particle size and secondary α (αs) size during the process of heating up to the solution temperature.These results may shed some light on the optimization of the knowledge-based heat treatment route.
基金项目
National Natural Science Foundation of China(51701219)
Doctoral Scientific Research Foundation of Liaoning Province(20180540133)
Special Project on Information Technology of the Chinese Academy of Sciences(XXH13506-304)
NETL
NSTL
万方数据