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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。
The effects of diffusion interface defects of φ4mm and φ2mm on the mechanical properties of Ti-6Al-4V alloy were studied. When the tensile load direction is parallel to the plane of the defect, the strength and ductility of the material is comparable to that of the defect-free material, since such defects have little effect on the area of the sample’s force-bearing cross-section. The tensile fatigue life of specimens with φ4mm defects showed a great dispersion, and the interface defects did not become the only sites of crack initiation. Samples that started from the surface were all in a high-life region, whereas most of the samples that started from the defect were in a low-life region. Finite element analysis shows that when the defect is located in the center, the stress concentration is small and the stress distribution gradient is small. When the defect locates at the edge, the stress concentration effect increases.