热爆合成-自发熔渗TiC/Fe_3Al复合材料的形成机理与磨损性能  

Formation mechanism and wear properties of TiC/Fe_3Al composites by thermal explosion synthesis and spontaneous melt infiltration

作　　者：迟静[1] 李敏[1] 王淑峰[1] 郭延章 吴杰[1] CHI Jing;LI Min;WANG Shu-feng;GUO Yan-zhang;WU Jie(College of Materials Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,Chin)

机构地区：[1]山东科技大学材料科学与工程学院,青岛266590

出　　处：《中国有色金属学报》2018年第7期1320-1327,共8页The Chinese Journal of Nonferrous Metals

基　　金：青岛市技术创新平台建设计划资助项目(14-7-2-42-gx);山东省自然科学基金资助项目(ZR2014EMM009)~~

摘　　要：采用热爆合成-自发熔渗方法快速制备TiC/Fe_3Al复合材料,通过相组成和显微组织的演变分析复合材料的形成过程,探讨TiC的生成及长大机制,并对复合材料的滑动摩擦磨损性能进行研究。结果表明:Ti、C热爆合成为TiC多孔压坯,Fe_3Al熔体自发渗入压坯孔隙;TiC在熔体中进行溶解-析出,结晶为初生TiC和共晶TiC。进入TiC晶格的Fe优先吸附在{100}晶面上,使其表面能降低,初生TiC形貌由{111}八面体转变为{100}立方体。TiC生长机制为小平面晶的台阶侧向生长,自发熔渗较快的冷却速度使生长台阶增多,形成叠层生长。TiC/Fe_3Al复合材料的滑动磨损率为2.7×10^(-7) g/s,比Fe_3Al的下降31.7%。磨损机理研究表明TiC有效抑制了剥层磨损,使复合材料的耐磨损性能提高。TiC/Fe3Al composites were fabricated rapidly by the combination of thermal explosion synthesis and spontaneous melt infiltration. The formation mechanism based on the phase composition and microstsucture evolution process, TiC growth mechanism, sliding friction and wear properties of the resultant materials were investigated systematically. The molten Fe3Al spontaneously infiltrates the pores of porous TiC compacts prepared by thermal explosion synthesis using Ti and C powders, resulting in the creation of TiC/Fe3Al composites. The formation of TiC in fmal products can be attributed to dissolution-precipitation mechanism, i.e., TiC dissolves in Fe3Al melt and decomposes into Ti and C, the latter reacts in the molten pool and precipitates the primary TiC and eutectic TiC during the cooling process. Fe atoms can enter the TiC lattice and be adsorbed preferentially at the { 100} crystal plane, giving rise to reduce the surface energy of the { 100} plane, so, the morphology of primary TiC changes from { 111 } octahedron to { 100} cube. The TiC growth pattern is lateral growth of facet crystals, tending to grow layer by layer depend on more growth steps provided by the high cooling rate during the fabricate process. The sliding wear rate of TiC/Fe3A1 composites is 2.7× 10^- 7 g/s, decreased by 31.7% compared with that of Fe3Al. The wear mechanism indicates that the wear resistance of the composites can be improved noticeably because the addition of TiC may effectively inhibit the delamination wear.

关 键 词：TiC/Fe3Al 热爆合成 自发熔渗 生长机制 磨损 

分 类 号：TB331[一般工业技术—材料科学与工程]