Study On Stress-strain Field And Microstructure Of316Stainless Steel By Laser Irradiation

In the paper ANSYS finite element analysis software is used to simulate the sample’stemperature field, stress field and strain field of the316stainless steel during the laserirradiation. On this basis, the laser surface treatment equipment developed by ourselves isapplied to do the laser irradiation test on the316stainless steel. And the microstructureand properties of the316stainless steel by the laser irradiation are studied by using theoptical metallographic microscope, scanning electron microscope (SEM), transmissionelectron microscope (TEM), X-ray diffraction analysis, hardness test, electron backscatterdiffraction (EBSD) and other modern analysis means. The results show that316stainlesssteel produces the obvious plastic deformation, parallel slip bands and grain relief formedby the laser irradiation. During the laser irradiation of (600-800)℃×(50-1000) cycles,when the maximum temperature is certain, the plastic deformation of316stainless steelbecomes larger with the increase of irradiation times; and when the irradiation times iscertain, the higher the maximum temperature, the larger the plastic deformation. Jade6.0isused to analyze the X-ray spectrum and calculate the microstructure parameters, thecalculated results turns out that the microstrain, the dislocation density and twinprobability of316stainless increase significantly by the laser irradiation. However, itmakes the crystallite sizes reduce obviously and the surface microstructure refinesapparently. The analysis of transmission electron microscopy (TEM) indicates that bylaser irradiation the316stainless steel produces a large number of dislocation, subgrainand twinning, and also shows that the dislocation density becomes larger and the subgrainsize becomes smaller with the increase of irradiation times, which causes the increase ofhardness. The results of EBSD analysis indicate that small angle grain boundaries increaseobviously by laser irradiation. And when the maximum temperature is certain, the numberof small angle boundaries increases with increasing irradiation times. Hardness of the316stainless steel in solid solution state increases by laser irradiation, which makes it obtains adeeper hardening layer.