原位拉伸法研究GH3625合金退火孪晶界稳定性及断裂行为

Stability of Annealing Twin Boundaries and the Fracture Behavior of GH3625 alloy during in situ Tension

摘要:

孪晶界面作为低能稳定界面且易在低层错能金属中被调控成为近年来研究的热点,固溶态GH3625合金组织中含有大量退火孪晶组织,本文采用室温原位拉伸结合扫描电子显微镜(SEM)观察和能谱(EDS)分析的方法研究了固溶态GH3625合金组织中孪晶组织演变及断裂行为。结果表明,GH3625合金在拉伸变形过程中,孪晶组织内部主要以单滑移为主；在拉伸直至断裂的过程中,随变形量的增加,孪晶界逐渐发生弯曲,但孪晶界始终存在于合金组织中,起阻碍位错的作用,具有良好的室温机械稳定性。GH3625合金断裂时既有韧性断裂又有脆性断裂,碳化物偏析是造成晶界裂纹以及晶内孔洞形成的主要原因。

Abstract:

_{: Twin boundary as a low energy stable interface and easy to be regulated in low stacking energy metals has become a hot focus in recent years. There are a lot of annealing twin structures in the solid solution GH3625 alloy. In this paper, the annealing twin structure evolution and the fracture behavior of GH3625 were studied by in situ tension at room temperature, which combined with Scanning Electron Microscopy (SEM) observation and Energy Dispersive Spectrometer (EDS) analysis. The results show that the deformation mode in the twin structure of GH3625 alloy is mainly single slip in the process of tensile deformation, and the twin boundary gradually bends with the increase of deformation during the process of tensile and fracture, but the twin boundaries always exists in the alloy structure, which hinders the dislocation and has good mechanical stability at room temperature. There are both ductile fracture and brittle fracture in GH3625 alloy, the carbide segregation is the main cause of grain boundary crack and intragranular holes formation.}