V和Cr对超细WC-Co硬质合金Co粘结相成分与WC/Co界面组织结构的影响  

Effects of V and Cr additions on chemical composition of Co binder phase and microstructure of WC/Co interface of ultrafine WC-Co cemented carbides

作　　者：黄翔[1,2] 易丹青[1,2] 王斌[1,2] 刘会群[1,2] 陈丽勇[1,2] 李会会[1,2] 朱慧娟[1,2] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中南大学有色金属材料科学与工程教育部重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2016年第1期95-102,共8页Materials Science and Engineering of Powder Metallurgy

基　　金：国家发改委技术改造项目(20121743);国家自然科学基金资助项目(51474244)

摘　　要：采用粉末冶金法制备WC-30Co,WC-30Co-1VC和WC-30Co-1Cr3C2硬质合金（成分含量为质量分数,下同）,分别采用随炉冷却和水淬2种方式进行冷却,采用电子探针分析技术和高分辨率透射电镜,分析合金的Co相成分以及WC/Co界面结构,研究V和Cr元素对WC-30Co合金的Co粘结相成分与WC/Co界面结构的影响。结果表明：VC抑制晶粒长大的效果比Cr3C2更明显;在1 280~1 360℃下烧结时,V和Cr的添加可提高W在Co相中的固溶量,而在1 400℃烧结时,对W在Co相中的固溶量影响不大。水淬态合金的WC/Co界面发现层状的含Cr和V的析出相,且含V析出相的厚度明显大于含Cr析出相的厚度;可以推断界面析出相是在烧结过程而并非冷却过程中形成的;析出相的形成是Cr3C2和VC抑制WC晶粒长大的重要原因。In this work, the chemical composition of Co binder phase and the microstructure of WC/Co interface in WC-30 Co, WC-30Co-1VC and WC-30Co-1Cr3C2 ultrafine alloys fabricated by powder metallurgy method and then furnace-cooled and water–quenched were investigated by high resolution transmission electron microscopy（HRTEM） and electron probe microanalysis（EPMA）. The results show that VC can inhibit grain growth more obviously than Cr3C2. When the alloys sinters at the temperature between 1 260 ℃ and 1 360 ℃, adding V and Cr can increase the solubility of W in Co binder phase. However, when the alloys sinters at 1 400 ℃, V and Cr have no any significant effect on the solubility of W in Co binder phase. Lamellar precipitated phases containing of V and Cr are found at the interfaces of WC/Co in water-quenched alloys, and the thickness of V precipitated phase is much bigger than that of Cr precipitated phase. It can be deduced that these precipitated phases are formed at the sintering process and not the cooling process. The formation of V and Cr precipitations at the WC/Co interfaces is the key factor to inhibit the grain growth during sintering.

关 键 词：超细WC-Co硬质合金 VC CR3C2 Co相成分 析出相 

分 类 号：TG135.5[一般工业技术—材料科学与工程]