基于J积分的裂纹尖端激光修复效果研究

Research on Laser Repair Effect of Crack Tip Based on J-Integral

利用激光修复技术修复裂纹可以有效提升零件的断裂性能。本文以304不锈钢紧凑拉伸试件为研究对象,分别建立了热分析和力学分析有限元模型。首先模拟了不同激光工艺参数下裂纹尖端修复区温度场的分布情况,并分析了稀释率随激光工艺参数变化的关系;进而由基体材料成分、修复粉末材料成分和稀释率的关系得到修复区材料成分,最后模拟得到修复后的304不锈钢试件裂纹尖端J积分,分析激光参数对裂纹尖端J积分的影响规律。结果表明,当激光光斑直径和加热时间一定时,随着激光功率的增大,裂纹尖端J积分先减小后变大,在激光功率为1800 W时修复试件具备较好的断裂性能;当激光功率和加热时间一定时,随着光斑直径的增大,裂纹尖端J积分先减小后变大,在光斑直径为3 mm时修复试件具备较好的断裂性能。

Using laser repair technology to repair cracks can effectively improve the fracture performance of parts.This paper takes 304 stainless steel compact tensile specimens as the research object,and establishes thermal analysis and mechanical analysis finite element models respectively.First,the temperature field distribution of the repair area around crack tipunder different laser process parameters was simulated,and the relationship between the dilution rate and the laser parameters was analyzed.Furthermore,the material composition of the repair zone was obtained from the relationship between the matrix material composition,the repair powder material composition and the dilution rate.Finally,the J-integral of the crack tip of the repaired 304 stainless steel specimen was simulated,and the influence of laser parameters on the J-integral of the crack tip was analyzed.The results show that when the laser spot diameter and heating time are constant,as the laser power increases,the J-integral at the crack tip decreases first and then increases,and the repair specimen has better fracture performance when the laser power is 1800 W;When the power and heating time are constant,as the spot diameter increases,the J-integral at the crack tip decreases first and then increases.When the spot diameter is 3 mm,the repaired specimen has better fracture performance.