WC-TiC-TaC无金属粘结相硬质合金烧结过程中的物相转变与扩散行为 精灵论文.doc

WC-TiC-TaC 无金属粘结相硬质合金烧结 过程中的物相转变与扩散行为 张立1，陈述2，单成1，南晴1，程鑫1，马鋆1 5 （1. 中南大学粉末冶金国家重点实验室，长沙 410083； 2. 长沙矿冶研究院分析检测中心，长沙 410012） 摘要：采用 Cr、V 掺杂超细 WC 与 TaTiC2 型单一相成分 WC-36.5TiC-24.5TaC 复式碳化物 粉末为原料，采 用 1700 oC 、 20 MPa 高 温高压固相烧结工 艺，制备了 WC-3.65TiC-2.45TaC-0.47Cr3C2-0.28VC 无金属粘结相硬质合金。采用 X 射线衍射分析技术 10 研究了烧结过程中的物相转变，采用扫描电镜与能谱仪对合金微观组织结构特征进行了观察 与分析。结果表明，合金烧结过程中发生了 W 原子向复式碳化物中的大量固溶、TaTiC2 型 固溶体→TiWC2 型固溶体的物相转变以及 TiWC2 型固溶体粘结相中 Ta、Ti 原子向 WC 中 的反向固溶。合金固相烧结致密化主要机制为 W 原子与 Ta、Ti 原子之间的非平衡体扩散固 溶机制。W 原子在金属碳化物固溶体粘结相中的各向异性溶解－析出会显著削弱晶粒生长 15 抑制剂的功能、导致板状晶 WC 晶粒的形成。 关键词：关键词无粘结相硬质合金；烧结；物相转变；扩散行为；晶粒生长抑制；XRD 分 析 中图分类号：TG135+.5；TF125.3；TG115.21 20 Phase transformation and diffusion behaviors during the sintering process of WC-TiC-TaC binderless carbide ZHANG Li1, CHEN Shu2, SHAN Cheng1, NAN Qing1, CHEN Xin1, MA Yun1 (1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha (2. 410083, China; 25 2. Analysis and Testing Center, Changsha Mining and Metallurgy Research Institute, Changsha, 410012, China) Abstract: WC-3.65TiC-2.45TaC-0.47Cr3C2-0.28VC binderless carbide was prepared by solid phase sintering at the temperature of 1700 oC and pressure of 20 MPa. Ultrafine tungsten carbide doped with V and Cr and WC-36.5TiC-24.5TaC mixed carbide with TaTiC2 type phase composition were used as 30 the raw materials. X-ray diffraction technology was used to study the phase transformation during the sintering process. Scanning electron microscopy and energy dispersive X-ray spectroscopy were used to study the character of the microstructure. It was shown that during the sintering process W atoms dissolved on a mass scale into the crystal lattices of the mixed carbide, which resulted in the phase transformation of the solid solution from TaTiC2 type→TiWC2 type. Meanwhile, the reverse 35 dissolution of Ta and Ti atoms into the WC crystal lattices took place. The mechanism for the densification through solid phase sintering was dominated by the bulk diffusion among W a