烧结温度对WC-6.1Co超粗合金微观结构及性能的影响

Effect of Sintering Temperature on the Microstructures and Properties of WC-6.1Co Ultra-Coarse Grained Cemented Carbides

采用传统的低压烧结工艺制备了WC-6.1Co超粗硬质合金,并通过光学金相观察和力学、物理性能检测研究了烧结温度对该硬质合金的微观结构以及性能的影响规律。结果表明:低压烧结制备的合金中WC晶粒度随烧结温度的升高而增大,WC晶粒孔隙始终较少,且棱角较鲜明,组织发育完整。此外,虽然磁力和导热系数随烧结温度的升高分别单调下降和增加,但烧结温度为1430℃时,WC-6.1Co超粗硬质合金的强度和硬度较高,具有最优的综合性能。

WC-6. 1Co ultra-coarse grained cemented carbides were prepared by the traditional low- pressure sintering process The metallography observation and mechanical and physical character- izations have been performed to study the effect of sintering temperature on the microstructures and properties of the ultra-coarse grained cemented carbides. It is found that the grain size of WC increases with the sintering temperature increasing. Moreover, the WC grains keep less pores and present integrality of microstructures with distinct edges and corners. In addition, the coercive force and thermal conductivity monotonically decreasing and increasing, respectively, with the sintering temperature growing, however, the WC-6.1Co ultra-coarse grained cemented carbide sintered at 1 430 ℃ reached highest bending strength and hardness, and eventually gained the best comprehensive performance.