应力状态对单晶高温合金DD5显微组织的影响

Effect of stress state on microstructure of DD5 single crystal superalloy

利用高分辨扫描电镜观察了DD5单晶高温合金经1093℃无应力长期时效和1093℃/137 MPa拉伸蠕变试验后的组织,研究应力状态对单晶高温合金的显微组织以及TCP相析出行为的影响。结果表明:与无应力长期时效相比,应力促进了单晶高温合金中γ′相的筏形组织的形成;剪切应力能够促进45°筏形组织的形成,筏形组织的形态与应力状态密切相关,应力可以促进TCP相的析出。

Microstructure of DD5 single crystal superalloy after long-term stress-free aging at 1093℃and tensile creep test at 1093℃/137 MPa was observed by high resolution scanning electron microscopy(HRSEM),and the effect of stress state on the microstructure and precipitation behavior of TCP phase of the alloy was studied.The results show that compared with the stress-free long-term aging,the stress promotes the formation of raft-like microstructure ofγ′phase of the alloy.The shear stress can promote the formation of 45°raft-like microstructure,the morphology of the raft-like microstructure is closely related to the stress state,and the stress can promote the precipitation of TCP phase.