微气孔对铝合金激光冲击强化的影响

Effects of Micro-pores on Laser Shock Peening of Aluminum Alloy

针对激光熔覆后,部分材料基体表面会含有少量的微气孔,微气孔的存在直接导致在激光冲击处理期间材料机械性能的改变。进行铝合金整合微气孔的激光冲击强化数值模拟,在ABAQUS有限元软件中建立均匀基体和含有微气孔基体的二维轴对称有限元模型。研究熔覆层中的微气孔对激光冲击过程中,冲击波速度、残余应力场、表面塑性变形以及能量变化影响的数值模拟,对这些效应的基本机制进行了系统的研究。数值模拟结果表明,与均匀基体相比,微气孔周围存在显著的压应力,为抑制裂纹的萌生提供有力条件;微气孔的存在削弱了冲击波的传播速度,平均速度下降约3.94%;此外,微气孔的存在影响最终的能量吸收。

A small amount of micro-pores are formed on the substrate surface of some materials after laser cladding,and the existence of the micro-pores directly results in the mechanical properties of the material during the laser shock peening.The numerical simulation of micro-pores integrated laser shock peening of aluminum alloys was carried out.The two-dimensional axisymmetric finite element models of homogeneous substrate and micro-pore substrate were established in ABAQUS finite element software.The effects of micro-pores in the cladding layer on the velocity,the residual stress field,the plastic deformation and the energy change of the shock wave during laser shock processing were researched.The basic mechanisms of these effects have been systematically studied.The numerical simulation results show that there is significant compressive stress around the micropores compared with the homogeneous substrate.The existence of micro-pores weakens the propagation velocity of the shock wave,and the wave velocity decreases by about 3.94%.In addition,the existence of the micro-pores affects the final energy absorption.