T8钢表面W-Mo-Co多元共渗层的组织和性能

Microstructure and Properties of W-Mo-Co Co-diffusion Layer on T8 Steel

采用双层辉光离子渗金属技术在T8钢表面进行了W—Mo—Co多元共渗，研究了表面合金层的组织、相组成、成分、硬度、脆性以及与基体的结合强度。结果表明，舍金层由MeC＋MC型碳化物层和W、Mo、Co固溶体扩散层组成。碳化物层硬度很高，渗金属态HV0.025硬度高达1200～1400，固溶、时效处理后硬度升高至1400～1600左右；固溶体扩散层在渗金属态硬度较低，HV0.025硬度只有400～550，固溶、时效处理后硬度升高至800～1000。碳化物层与基体之间为冶金结合，不存在膜基结合问题。

Co-diffusion of W-Mo-Co was conducted on the surface of T8 steel by means of the double glow plasma surface alloying technique. Microstructure, phase composition, element distribution, microhardness, brittleness and bonding strength between surface alloyed layer and substrate were studied. The results show that the surface alloyed layer are composed of M6C＋ MC type carbide layer and solid solution layer of W,Mo,Co. Hardness of carbide layer are 1 200-1 400 HV0.025 and ageing treatment can not improve them significantly. Hardness of solid solution layer are only 400-550 HV0.025 and can be improved to 800-1000 HV0.025 by subsequent ageing treatment. The bonding strength between carbide layer and substrate were evaluated by scratch method. Because carbide layer grows from substrate by metallurgy method, no delamination occurs during scratching.