金属材料裂纹冲击韧性评定方法研究

工程结构在复杂环境下长期服役后，裂纹的萌生和发展难以避免。对于需要承受爆炸与冲击的工程结构，需要对所用材料的裂纹冲击韧性进行评定，避免裂纹出现可能导致的冲击脆性断裂。基于Instron VHS高速材料试验机，开发了一套材料动态断裂试验装置，测量了4种具有高冲击功金属材料的裂纹冲击韧脆转变过程，并研究了影响金属材料裂纹冲击韧脆转变速率的因素。发现材料夏比冲击功并不能完全反应裂纹的冲击韧性，预制裂纹与否、试样约束方式和试样裂尖约束因子都会影响金属材料裂纹冲击试验中的韧脆转变速率。基于以上研究结果，提出了金属材料裂纹冲击韧性评定方法的基本思路。 

Study on Crack Impact Toughness Evaluation Method for Metallic Materials

For the engineering structures in service for a long period in the complex environment, crack initiation and growth are difficult to avoid. Therefore, for the engineering structures required to withstand explosion and impact, the crack impact toughness of their materials must be evaluated to prevent the possible brittle fracture under impact due to crack occurrence. This study, relying on the Instron VHS high strain rate material testing machine, develops a set of dynamic fracture testing device to measure the crack ductile-brittle transition process of 4 different kinds of metallic material with high impact energy under impact, and studies the factors influencing the crack ductile-brittle transition rate of these materials. According to the findings, the Charpy impact energy can not fully reflect the crack impact toughness,and the absence and existence of preformed cracks, the specimen constraint mode and the specimen crack tip constraint factor all have an effect on the ductile-brittle transition rate in the crack impact test of metallic materials. Based on the results above, this study finally propose the basic ideas about the crack impact toughness evaluation method for metallic materials.