超细WC-Co硬质合金的制备与性能研究

利用高能球磨法制备纳米级WC-Co混合粉末,采用脉冲电流烧结技术进行烧结。用能谱分析仪(EDX)对球磨后的粉末进行成分分析,用X射线衍射(XRD)对比分析球磨前后WC-Co混合粉末的衍射峰变化,用透射电子显微镜(TEM)和扫描电子显微镜(SEM)对所制备的粉末及烧结材料进行了组织形貌观察,并测定了烧结试样的硬度。结果表明:随着球磨时间的延长,WC-Co纳米粉末的粒度逐渐变小,当球磨时间超过30h后获得了粒度为100nm以下的WC-Co纳米粉末。脉冲电流烧结后获得超细WC-Co硬质合金,与传统的WC-Co硬质合金相比,超细WC-Co硬质合金具有更高的硬度(HRA92.5～94)和耐磨性。另外通过实验获得了最佳的烧结工艺参数。

Study on Preparation and Mechanical Properties of WC-Co Ultrafine Cemented Carbides

In this paper the nanostructured WC-Co powder was fabricated by high-energy ball milling and also sintered by pulse electric current sintering subsequently. The component of milled powder was analyzed by means of EDX. The fluctuations of diffraction peak between milled powder and WC-Co powder were analyzed by XRD. The structures of powder and sintered alloy were analyzed by means of TEM and SEM,the hardness of sintered alloy was measured too. The results show that the grain of nanostructured WC-Co powder decreases with the increase of milling time. When the milling time exceeds 30 hours,the nanostructured WC-Co powders with grain size under 100nm can be fabricated. Ultrafine cemented carbides can be prepared by pulse electric current sintering process. Comparing with the conventional ones,ultrafine cemented carbides exhibite more higher hardness (HRA92.5～94)and abrasion-resistant. In addition,the best technique of sintering was obtained by experimenting.