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 bydislocations.During stabilization annealing treatments,the,anddislocations 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.

Jinlong Su;Xiankun Ji;Jin Liu;Jie Teng;Fulin Jiang;Dingfa Fu;Hui Zhang

College of Materials Science and Engineering,Hunan University,Changsha 410082,China;AECC Hunan Aviation Powerplant Research Institute,Zhuzhou 412002,China

材料科学技术（英文版）

[1]Jinlong Su;Xiankun Ji;Jin Liu;Jie Teng;Fulin Jiang;Dingfa Fu;Hui Zhang-.Revealing the decomposition mechanisms of dislocations and metastable α'phase and their effects on mechanical properties in a Ti-6Al-4V alloy)[J].材料科学技术（英文版）,2022(12):136-148

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