摘要
采用渗氮烧结工艺制备YT15梯度硬质合金,利用扫描电镜、能谱仪、X射线衍射等手段,研究该合金的表面微观组织,并对其表面梯度层的形成进行热力学分析。结果表明Ti元素与N元素之间较强的结合力驱动Ti元素向外和Co元素向内定向迁移,在合金表面形成厚度为10μm的富含Ti(C,N)相的梯度层。实验结果与热力学分析均表明氮气氛烧结可使合金中的Ti元素向表面迁移,从而形成表面富含Ti(C,N)硬质相的梯度硬质合金。合金中出现粗大的WC晶粒,且表面梯度层较薄,制备工艺有待进一步优化。
The influence of nitriding sintering on the surface microstructure of the YT15 cemented carbides was investigated,using scanning electron microscope（SEM）,energy dispersive X-ray spectrometry（EDS） and X-ray diffractometry（XRD）.The formation of the graded layer was analyzed by thermodynamics.The nitriding sintering resulted in the formation of a graded surface layer,which is rich in Ti（C,N）.The formation of this surface is attributed to the high atom affinity between titanium and nitrogen,which is the driving force for outward transport of titanium and inward transport of cobalt.Both the experimental results and thermodynamic analysis indicate that nitrogen atmosphere can make the titanium transport to the surface and form graded cemented carbides.For the presence of coarse WC grains and thin graded layer,the process should be optimized.
出处
《粉末冶金材料科学与工程》
EI
2011年第3期437-441,共5页
Materials Science and Engineering of Powder Metallurgy
基金
重庆市科技攻关资助项目(CSTC2009AB4137)
重庆市教委资助项目(KJ111212)
