Abstract
The metastable α'phase and dislocation characteristics(e.g.,density and constituents)are of vital im-portance for the mechanical responses of(α+β)titanium alloys.In this work,to reveal the in-depth de-composition mechanisms of dislocations and metastable α'and their influences on mechanical properties in a Ti-6Al-4V(α+β)alloy,the thermal stability of different microstructures tailored by various cooling approaches were investigated utilizing scanning electron microscope,electron backscattered diffraction,transmission electron microscope and X-ray diffraction line profile analysis.The results showed that the initial characteristics of α'and α laths and dislocation density were influenced by the cooling methods remarkably.The thermal stability of Ti-6Al-4V alloy increased with decreasing cooling rate.The improve-ment in thermal stability can be ascribed by the decrement in dislocations,partitioning of the alloying elements and grain orientations variation of the α'lath and α phase.It is also found that the plastic strain accommodation of β→α'transformation was dominated by<a>dislocations.During stabilization annealing treatments,the<a>,<c>and<c+a>dislocations simultaneously decomposed.The decompo-sition of dislocations and metastable α'phase during various stabilization annealing and the particular twins and stacking faults microstructures formed during quenching have a great influence on the proper-ties of the studied Ti-6Al-4V alloy.
基金项目
National Natural Science Founda-tion of China(51774124)
National Natural Science Founda-tion of China(52074114)
Hunan Provincial Natural Sci-ence Foundation of China(2019JJ40017)
Hunan Provincial Natural Sci-ence Foundation of China(2020JJ5062)
Graduate Training and Innovation Practice Base of Hunan Province()
NETL
NSTL
万方数据