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通过拉伸及卸载试验,对试样断口与表面进行SEM观察分析,研究TiAl基合金拉伸损伤与断裂行为。结果表明:该材料拉伸的弹性阶段范围很窄,塑性变形能力差,在拉伸卸载试样表面观察不到微裂纹和损伤;而在试样断口上有唯一起裂源和发散状的河流花纹。断裂过程为:当试样被加载至一定应力时,在其应力最大截面附近某一材料组织薄弱处率先产生一定尺寸的Griffiths裂纹源,并很快由此起裂源朝多个有利取向快速解理扩展,并导致试样最后完全断裂。
Through the tensile and unloading tests, the fracture surface and the specimen SEM observation and analysis of TiAl-based alloys tensile damage and fracture behavior. The results show that the material has a narrow elastic range, poor plastic deformation ability, no microcracks and damage on the surface of the tensile unloading specimen, and only the source of the fracture and the divergent river Pattern. The fracture process is as follows: when the sample is loaded to a certain stress, a Griffiths crack source of a certain size will be firstly produced at a certain weakness of the material structure near the maximum stress section, and the cracking source will quickly move toward a plurality of favorable oriented rapid solutions Reasonable expansion, and led to the specimen completely broken.