扩散连接界面缺陷对Ti-6Al-4V合金力学性能的影响

研究了φ4mm与φ2mm的扩散连接界面缺陷对Ti-6Al-4V合金力学性能的影响。当拉伸载荷方向与缺陷平面平行时,材料的强度与塑性与无缺陷材料相当,这是由于此类缺陷对样品受力截面的面积几乎没有影响。含有φ4mm缺陷试样的拉压疲劳寿命展现出很大的分散性,界面缺陷并未成为裂纹萌生的唯一位置。从表面起裂的样品均处于高寿命区域,而绝大部分从缺陷处起裂的样品均落于低寿命区域。有限元分析表明,当缺陷位于中心位置时其引起的应力集中较小,应力分布梯度较小;缺陷位于边缘位置时,应力集中效应增大。

Effect of Diffusion Bonding Defect on Mechanical Properties of Ti-6AI-4V Alloy

The effect of diffusion bonding (DB) defect with φ 4mm and φ 2mm diameter on mechanical porperties of Ti-6Al-4V alloy is investigated.The defect plane is parallel to the load axis,the strength and ductility of the material are not affected because the area subjected to tensile load almost stayed the same.Ti-6Al-4V alloy with φ4mm DB defect under fully reversed fatigue load exhibited a large scatter of life,and the defect is not the unique crack initiation area.Samples with surface crack initiation exhibited longer fatigue life;while almost all samples with defect-induced crack initiation exhibited a much shorter fatigue life.Finite element analysis shows that the stress concentration is lower when the defect is in center;The stress concentration is higher when the defect is on edge.