Relationship of fracture behavior and stress triaxiality of additive manufactured Ti-6Al-4V

增材制造Ti-6Al-4V合金断裂行为与应力三轴度关系研究

¹ School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China
² Scientific Research Management Department, Aircraft Strength Research Institute, Xi'an 710065, China

Received: 15 December 2021

Abstract

It is significant to study the relationship between the stress triaxiality and the fracture behavior for analyzing the failure process of additive manufactured titanium alloy. This paper combined the tensile test of smooth round bar specimens and notched round bar specimens with the numerical simulation to obtain the stress triaxiality distribution and fracture strain in order to study fracture behavior of additive manufactured titanium under different stress triaxiality. Fracture analysis was proceeded by using scanning electronic microscope to analyze the correlation between the stress triaxiality and the fracture behavior. Results show that the fracture strain decreases while the stress triaxiality increases and the location of the crack initiation moves from the center to the edge of the minimum cross-section while the radius of the notch decrease.

摘要

研究应力三轴度与增材制造钛合金材料断裂行为的相关性, 对分析增材制造钛合金的断裂失效过程有着重要的作用和意义。对光滑圆棒和缺口圆棒试件在准静态下进行单轴拉伸试验, 结合数值仿真分析得到试件的应力三轴度分布和断裂应变, 研究了增材制造钛合金在不同应力三轴度下的韧性断裂行为。通过扫描电子显微镜观察试件断口表面的形貌, 分析不同应力三轴度下增材制造钛合金的断裂机理。研究发现, 在中高应力三轴度范围内, 增材制造钛合金的断裂应变随应力三轴度的升高而降低; 缺口圆棒试件的起裂位置随缺口半径的减小从最小截面中心处逐渐转移至边缘处。