激光涂敷对低合金钢高温性能的影响

Effects of laser coatings on high temperature properties of low alloying steel

本文研究了利用激光表面涂敷技术改善材料高温性能的可能性。实验结果表明 :经激光涂敷处理之后 ,材料表面的高温性能明显优于基体材料本身。在 70 0℃时 ,表层的硬度比基体硬度高出 76 6 7% ,达到了HV15 90MPa。相应地 ,表面涂敷层的冷热疲劳抗力提高了 16 6 6 7% ,且其抗裂纹扩展的能力明显增加。另一方面 ,与原始涂敷合金材料相比较 ,激光涂敷层的化学成分没有大的变化 ,其主要合金元素的浓度变化率小于 6 6 7%。试验还发现 :当采用搭接技术进行激光扫描时 ,其显微组织出现了组织梯度现象。这一现象对材料的性能影响尚有待于进一步研究。

The possibility of improving high temperature properties of materials by laser coating was studied,in the paper.The experimental results show that high temperature properties of surface coating layer are superior to that of substrate material.The hardness of surface layer coated by laser is as high as HV1590 MPa,which is 0.77 times higher than the hardness of substrate,under 700℃ high temperature.Correspondingly,the resistance to thermal shocks of the coating layer is also obviously increased to go up 166.67%,as compared with untreated material.On the other hand,the capacity to resist micro crack propagation could be improved,by laser coating.Finally,the findings confirm that constituent changes for main alloying elements in the surface layer are smaller than 6.67 percent,after laser irradiation,as compared with original coating material.