硬质合金中WC晶面取向分布形成的机理研究  

Mechanisms for formation of WC plane orientation in cemented carbides

作　　者：王西龙[1] 刘雪梅[1] 王海滨[1] 刘兴伟[1] 宋晓艳[1] 

机构地区：[1]北京工业大学材料科学与工程学院/新型功能材料教育部重点实验室,北京100124

出　　处：《中国体视学与图像分析》2016年第1期107-116,共10页Chinese Journal of Stereology and Image Analysis

基　　金：国家杰出青年科学基金(No.51425101);北京市自然科学基金重点项目(No.2131001)

摘　　要：采用本研究组原创的原位合成短流程专利技术,结合制备方案和工艺参数优化,研制出了具有高度WC特征晶面取向分布的WC-Co硬质合金块体材料。利用X射线衍射分析和背散射电子衍射(EBSD)方法对所制备的硬质合金材料的物相组成、取向特征进行了系统的表征研究,同时对WC特征晶面取向分布形成机理从粉末物相组成和烧结过程参数两个方面进行了分析讨论。研究结果表明:WC晶粒呈现明显的板状晶,硬质合金块体在垂直于烧结压力方向上具有WC晶粒基面(0001)择优取向分布,在平行于烧结压力方向上,基面面积分布比例明显减少,相应的出现了WC晶粒柱面(10-10)的择优取向分布。粉末中缺碳相含量和烧结过程中辅助压力的大小对最终制备的合金块体WC晶粒的取向分布起着决定性的作用,缺碳相在烧结的过程中进一步碳化形成板状WC晶粒并在压力的作用下趋于基面垂直于压力方向分布为块体中WC特征晶面取向分布的主要形成机制。WC- Co cemented carbides with highly oriented WC grains were prepared by a novel method combining in situ reactions and spark plasma sintering with optimized parameters. The characteristics of phase constitution and WC plane distribution of the prepared bulk material were characterized by XRD and electronic back scattered diffraction（ EBSD） systematically. Moreover,the mechanisms of WC grain orientation distribution were studied in the aspects of carbon lack phases in the composite powder and sintering pressure. The results show that the microstructure has obviously higher fraction of the WC basal plane（ 0001） on the cross- section which is perpendicular to the pressing direction of the sintering powder. However,on the cross- section parallel to the sintering pressure direction,the fraction of the prism plane（ 10- 10） is the highest. The content of carbon lack phases and sintering pressure are crucial to the orientation formation in prepared bulk samples. The carbon lack phases transform to WC in the process of sintering accompanied by grain rotation towards the direction perpendicular to the（ 0001）plane.

关 键 词：EBSD 基面择优分布 硬质合金 板状晶 

分 类 号：TG135.5[一般工业技术—材料科学与工程] TB383[金属学及工艺—合金]