钛铝合金原位拉伸损伤与断裂过程

In-situ Tensile Damage and Fracture Process of Titanium Aluminum Alloy

通过原位拉伸及卸载试验,利用SEM分析试样断口与表面形貌,对钛铝合金原位拉伸断裂过程、断裂起始点及断裂扩展情况进行了研究。结果表明,该材料断口上呈现沿层断裂和穿层断裂的混合形态,并在裂纹前端取向不利的层团附近出现大量微裂纹损伤。发现其断裂过程为:随着外加载荷的增加,试样首先在晶粒沿层薄弱区开裂,继续加载会在主裂纹前端附近产生一些微裂纹损伤,接着裂纹将穿层断裂,同时积蓄的能量得到部分的释放,直至试样的整体断裂。

Through in-situ tensile and unloading tests,the fracture and surface morphology of the samples were analyzed by SEM,and the in-situ tensile fracture process,fracture initiation point and fracture propagation of TiAl alloy were studied.The results show that the fracture of the material presents a mixed morphology of inter-lamellar fracture and trans-lamellar fracture,and a large number of microcrack damage occured near the layer cluster with unfavorable orientation at the front of the crack.The fracture process is that the specimen first produced crack in the weak area of inter-lamellar with the increase of applied load.Then some microcrack damage will be generated near the front end of the main crack,thereafter the crack will break trans-lamellar;part of the accumulated energy will be released at the same time.Finally,the whole specimen was fractured.