Ti6321钛合金动态断裂行为研究

Research on dynamic fracture behavior of Ti6321 Titanium Alloy

摘要:

对Ti6321钛合金进行动态三点弯曲加载，使其发生I型（张开型）断裂并获得波形曲线，结合实验-数值法获得了三种组织Ti6321钛合金的I型裂纹动态断裂性能。利用扫描电镜、激光共聚焦显微镜对三种组织Ti6321钛合金的断口进行观察分析。结果表明，魏氏组织具有最高的I型裂纹动态断裂性能，双态组织次之，等轴组织的动态断裂性能最低。对于I型裂纹断口，等轴组织与双态组织主要为韧性断裂机制，而魏氏组织呈现出部分解理断裂的特征。魏氏组织断口的起伏最大，比表面积最大，裂纹扩展需要消耗更多能量，因此断裂性能较好。

关键词:Ti6321钛合金;动态断裂;I型裂纹;断裂特征

Abstract:

The dynamic three-point bending loading was carried out on Ti6321 titanium alloy to cause mode I (open type) fracture and obtain the waveform curve. Combined with the experimental & numerical method, the mode I crack dynamic fracture properties of Ti6321 titanium alloy with three structures were obtained. The fracture surfaces of three kinds of Ti6321 titanium alloys were observed and analyzed by scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM). The results show that the widmanstatten structure has the highest dynamic fracture performance of mode I crack, followed by the bimodal structure, and the equiaxed structure has the lowest dynamic fracture performance. For mode I crack fracture, equiaxed structure and bimodal structure are mainly ductile fracture mechanism, while widmanstatten structure has the characteristics of partial cleavage fracture. The Widmanstatten structure has the best fracture performance. Because of the largest fluctuation of fracture and the largest specific surface area, the crack propagation needs more energy.

Key words:Ti6321 titanium alloy; dynamic fracture; mode I crack; fracture characteristics