以10CrNi3MoV钢、5083铝合金、500-7球墨铸铁3种不同塑性的金属材料为研究对象，分别加工光滑和缺口试样，通过对比试样的拉伸性能及断口形貌，研究了缺口对不同塑性金属断裂行为的影响。结果表明：缺口改变了材料的应力状态，减少了剪切方向的变形，提高了试样正拉断裂的比例。对于塑性材料，缺口根部可以通过塑性变形来缓解应力集中，且缺口深度越大，材料塑性越好，抗拉强度越高；对于脆性材料，缺口根部产生的应力集中会导致拉伸过程中试样过早断裂，降低材料的抗拉强度。

Three kinds of metal materials with different plasticity of 10CrNi3MoV steel, 5083 aluminum alloy and 500-7 nodular cast iron were used as the research objects, and the smooth and notched specimens were processed respectively. The effect of notch on the fracture behavior of the metals with different plasticity was studied by comparing the tensile property and fracture morphology of specimen. The results show that the notch changed the stress state of material, reduced the deformation in the shear direction and improved the proportion of normal tensile fracture. For plastic materials, the notch root could alleviate the stress concentration through plastic deformation, and the larger the notch depth, the better the plasticity of material and the higher the tensile strength. For brittle materials, the stress concentration on the notch root would lead to the premature fracture of specimen during the tensile process and reduce the tensile strength of materials.