Research into Functionally Graded Cemented Carbide:Microstructure Evolution of Specifically Engineered Surface Layer and Gradient Formation Mechanisms
The paper investigated two functionally graded cemented carbides with unique tailored surface and gradient structures.The engineered surfaces of functionally graded cemented carbides were tailored by controlling the starting formulation and the sintering atmosphere during liquid phase sintering.The first functionally graded cemented carbide in this study has fcc(Face Centered Cubic)phase rich surface layer,which is introduced during sintering in a nitrogen atmosphere.The high TiC content in this first functionally graded carbide is critical to the formation of the surface layer,which involves the Ti outward diffusion from core to the surface and the Co inward migration from surface to subsurface during liquid phase sintering.The second functionally graded cemented carbide in this study has surface layer of high Co contents,which is introduced during sintering in a nitrogen-deficiance atmosphere.The high TiN content in this carbide is critical to the formation of high Co surface layer,which involves the decomposition of TiN and the subsequent Co outward migration from core to surface during sintering.They were fabricated by a tailored sintering technique based on the selective de-nitriding of the near-surface layer of carbide green bodies with original high TiN contents resulting in Co drifts from the core towards the surface during liquid-phase sintering.Such functionally graded cemented carbides may provide unique surface microstructure beneficial to further PVD coating(Physical Vapor Deposition)or CVD coating(Deposition Chemical Vapor).
Cemented carbides Functionally graded carbides Surface engineering Diffusion
Ji Hongwei Chen Jian Deng Xin Wu Shanghua
School of Electromechanical Engineering,Guangdong University of Technology Guangzhou,Panyu district,510006,China
国际会议
北京
英文
834-839
2018-09-16（万方平台首次上网日期，不代表论文的发表时间）