5CrNiMo热浸镀铝激光重熔层组织观察

Microstructure observation of coating prepared by hot-dipped aluminum and laser remelting on the surface of 5CrNiMo

将5CrNiMo钢在(720±5)℃热浸镀纯铝,对其进行激光重熔。利用金相显微镜及扫描电镜对重熔合金层及结合界面组织进行了观察。结果表明:热浸镀铝层经950℃×6h扩散退火处理后裂纹明显;而激光重熔后获得了致密、无肉眼可见气孔和夹杂等缺陷的重熔层,合金层与基体之间为完全的冶金结合;组织呈完整的树枝晶,结合界面处为粗大的树枝晶,外层逐渐变成细小的枝晶;EDS结果表明重熔层中成分相对均匀,重熔层中的主要相为Fe(Ni、Cr)3Al及Ni3Al。

The coatings were prepared by hot dipped aluminum and laser remelting on the surface of5CrNiMo.The microstructure of the coating and the boundary between the coating and substrate were studied by SEM. The coating jointed metallurgically with the steel substrate with no pores. The microstructure of coating appeared complete dendrite. The coarse dendrite lay in the boundary ,and became more smaller fi＇om boundary to the outer. The main phases were Fe（Ni,Cr）3Al and Ni3Al in the remelting layer.