Effective femtosecond laser shock peening on a Mg-3Gd alloy at low pulse energy 430 μJ of 1 kHz

摘要

In this paper,microstructure evolution and hardness of Mg-3 Gd alloy treated by femtosecond(fs)laser shock peening(LSP)with direct and confined ablation m odes were investigated in detail.Under a relatively low pulse energy of 430μJ with a repetition of 1 kHz,the surface hardness of sample has been enhanced by 70%effectively.Comp a r e d with ns-LSP with pulse fluence of 71.7J/cm2,fs-LSP with pulse fluence of 34.2 J/cm2 is superior in the hardness increment,both of which are in the same order of magnitude.A distinct grain refinement of surface layer has been discovered and results in the increase of hardness.Nonuse of absorption and confining layers and the employment of the industry commercial fs laser with high repetition can inspire big potential L S P application in special metal material.©2019 Published by Elsevier B.V.on behalf of Chongqing University.