Huaming WANG
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Xijun SUN
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Xiaoxuan LI
材料科学技术（英文）
An austenitic stainless steel 1Cr18Ni9Ti and a solid solution-strengthened Ni-base superalloy GH30 were shock processed using a Q-switched pulsed Nd-glass laser. Microstructure, hardness and residual stress of the laser shock processed surface were investigated as functions of laser processing parameters. Results show that high density of dislocations and fine deformation twins are produced in the laser shock processed surface layers in both the austenitic stainless steel and the nickel-base superalloy. Extensive strain-induced martensite was also observed in the laser shock processed zone of the austenitic steel. The hardness of the laser shock processed surface was significantly enhanced and compressive stress as high as 400 MPa was produced in the laser shock processed surface.
关键词:
Laser shock processing
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Y.X. Hu
,
Z.Q. Yao
金属学报(英文版)
Finite element method is presented to attain the numerical simulation of residual stresses field in the material treated by laser shock processing. The distribution of residual stresses generated by single laser shock with square and round laser spot is predicted and validated by experimental results. With the FEM model, effects of different overlapping rates and impact sequences on the residual stresses distribution are simulated. And the results indicate that: (1) Overlapping laser shock can increase the compressive residual stresses. But it is not effective on the growth of plastically affected depth; (2) Overlapping rate should be optimized and selected carefully for the large area treatment. Appropriate overlapping rate is beneficial to obtain a homogeneous residual stress field; (3) Impact sequence has a great effect on the residual stress field. It can greatly attenuate the phenomenon of “residual stress hole” to obtain a homogeneous residual stress field.
关键词:
Laser shock processing
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