Study on Concentrating Behavior of Binder on Surface of Ti(C,N)/AlCoCrFeNi Cermets During Sintering
ZHU Gang1, CHEN Jialin1, JIA Hailong1, LIU Ying2, XIE Ming1
1 State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals, Kunming Institute of Precious Metals, Kunming 650106; 2 School of Materials Science and Engineering, Sichuan University, Chengdu 610044
Abstract: Through the analysis of surface topography and phase composition of the alloy, the concentrating behavior of binder on the surface of Ti(C,N)/AlCoCrFeNi cermets during sintering process were studied. The results indicated that the binder was obviously concentrated on surface when sintered under 1 300 ℃ for 60 minutes, and formed a third phase containing M6C-type brittle phase (η). This phenomenon could attribute to the carbon concentration difference, solid solution concentration difference and temperature difference of the surface and interior, which caused by decarbonization during sintering. It urged the migration of W, Ta, Ti, Mo to the interior in a diffusion way. Besides, the surface decarbonization also caused the increase of alloy eutectic temperature. Thus, the reduction of surface liquid phase leaded to the generation of negative pressure, which made the inner liquid phase transfer to the surface. In addition, binding phase regions with different volume content in the microstructure might lead to the pressure difference, and the rich W region was apt to migrate to the poor W region with low liquid phase during sintering, which caused the binding phase transfer, permeate and finally gathered on the surface.
1 Yeh J W,Chen S K, Lin S J, et al. Nanostructured high-entropy alloys with multiple principal elements: Novel alloy design concepts and outcomes[J]. Adv Eng Mater,2004,6:299. 2 Yeh J W,Chen S K,Gan J Y, et al. Formation of simple crystal structures in solid solution alloys with multi-principle metallic elements[J]. Metall Mater Trans A,2004,35A(8):2533. 3 Wu J M, Lin S J, Yeh J W, et al. Adhesive wear behavior of AlxCoCrFeNi high-entropy alloys as function of aluminum content[J]. Wear,2006,261:513. 4 Chen T K,Shun T T,Yeh J W, et al. Nanostructured nitride films of multi-element high-entropy alloys by reactive DC sputtering[J].Surf Coat Technol,2004,188:193. 5 Zhu Gang,Liu Ying,Ye Jinwen. Fabrication and properties of Ti(C,N)-based cermets with multi-component AlCoCrFeNi high-entropy alloys binder[J].Mater Lett,2013,113:80. 6 Zhu Gang,Liu Ying,Ye Jinwen. Early high temperature oxidation behavior of Ti(C,N)-based cermets with multi-component AlCoCr-FeNi high-entropy alloys binder[J]. Int J Refract Met Hard Mater,2014,44:35. 7 Janisch D S, Lengauer W, Rodiger K, et al. Cobalt capping: Why is sintered hardmetal sometimes covered with binder [J]. Int J Refract Met Hard Mater,2010,28:466. 8 Guo J,Fan P,Wang X, et al. Formation of Co-capping during sintering of straight WC-10 wt% Co[J]. Int J Refract Met Hard Mater,2010,28:317. 9 Sachet E, Schubert WD, Mühlbauer G, et al. On the formation and in situ observation of thin surface layers of cobalt on sintered cemented carbides[J]. Int J Refract Met Hard Mater,2012,31:96. 10 Zhang Yizhong, Xie Hong, Li Kun. Formation of Co-capping during sintering of ultrafine WC-10%Co cemented carbide[J]. Cemented Carbide,2011,28(6):358(in Chinese). 张益中,谢宏,李昆.WC-10%Co超细硬质合金烧结中表面钴聚集的形成[J].硬质合金,2011,28(6):358. 11 Wu Jianguo. Research on the η phase in decarburized zone of gra-dient cemented carbide [J]. Cemented Carbide,2008(6):79(in Chinese). 吴建国.梯度合金中脱碳区η相的研究[J].硬质合金,2008(6):79. 12 铃木寿.含氮WC-β-Co合金烧结块表面生成的脱β层[J]. 日本金属学会志,1981,45(1):11.
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2017, Vol. 31 
