Effect of Re-sintering on Co Gradient Structure of Dual-phase Structured WC-Co Cemented Carbide

摘要：

　　A cobalt gradient WC-Co cemented carbide with dual phase structure was re-sintered in vacuum at 1460 ℃ for 120 min.This alloy was characterized by three distinct zones,namely surface zone with lower cobalt content and higher hardness,intermediate zone with substantially higher cobalt content and substantially lower hardness,and core zone with η(Co3W3C) phase.The change in microstructure,Vickers hardness (HV2),and propagation characteristic of the cracks produced at the opposite corners of Vickers indents (HV50) along the direction of gradient was observed.The results showed that there still existed cobalt gradient in the alloy after the re-sintering; nevertheless,the initial low-hardness abrupt zone vanished and the hardness declined gradually along the direction of gradient,with improved hardness in the initial surface and intermediate zones.The ηphase in the initial core zone near the intermediate zone was eliminated.As a result,the thickness of surface zone and intermediate zone with WC+γ (cobalt based binder phase) structure broadened.After the re-sintering,the high toughness characteristics of the alloy still remained.The mechanism of cobalt migration and the reason behind the existence of the cobalt gradient at high temperature were discussed.

关键词： functionally graded cement carbide re-sintering cobalt gradient structure stability low-load Vickers hardness liquid migration pressure

作者: Xie Mingwei Zhang Li Nan Qing Wei Xing Feng Yuping Wang Zhe

作者单位: State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China

会议类型: 国际会议

会议名称: 2012 Zhuzhou International Conference on Cemented Carbides(株洲硬质合金国际学术会议)

会议地点: 株洲

会议语种:英文

页码: 114-121

在线出版日期: 2012-09-12（万方平台首次上网日期，不代表论文的发表时间）