摘要
Near net shaped Ti−45Al−7Nb−0.3W alloy(at.%)parts were manufactured by hot isostatic pressing(HIP).The microstructure and high-temperature mechanical properties of the alloy were investigated by X-ray diffractometry(XRD),scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The results show that at a temperature of 700℃,the peak yield stress(YS)and ultimate tensile stress(UTS)of alloy are 534 and 575 MPa,respectively,and the alloy shows satisfactory comprehensive mechanical properties at 850℃.The alloy exhibits superplastic characteristics at 1000℃ with an initial strain rate of 5×10^−5 s^−1.When the tensile temperature is below 750℃,the deformation mechanisms are dislocation movements and mechanical twinning.Increasing the tensile temperature above 800℃,grain boundary sliding and grain rotation occur more frequently due to the accumulation of dislocations at grain boundary.
采用热等静压(HIP)方法制造近净成形的Ti−45Al−7Nb−0.3W(摩尔分数,%)合金零件,并采用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)技术研究热等静压制备的Ti−45Al−7Nb−0.3W合金的显微组织和高温力学性能。结果表明,在700℃条件下,热等静压制备的合金的屈服强度和极限抗拉强度分别为534和575 MPa。该合金在850℃时表现出良好的综合力学性能。在变形温度为1000℃、初始应变率为5×10^−5 s^−1时合金表现出超塑性特性。当拉伸温度低于750℃时主要变形机制为位错滑移和机械孪生。当变形温度高于800℃时,位错在晶界堆积,促进晶界滑移和晶粒旋转。
基金
Project(51774335)supported by the National Natural Science Foundation of China
Project(2019JJ40374)supported by the Natural Science Foundation of Hunan Province,China
Project(CSUZC202004)supported by the Open Sharing Fund for the Large-scale Instruments and Equipments of Central South University,China。
