烧结温度对WC-14TiC-8Co超细硬质合金组织和性能的影响

Effects of Sintering Temperature on Microstructure and Properties of WC-14TiC-8Co Ultrafine Cemented Carbide

采用粉末冶金法制备了WC-14TiC-8Co超细硬质合金,研究了不同的烧结温度对WC-14TiC-8Co超细硬质合金组织和性能的影响。结果表明,随着烧结温度从1300℃升高到1410℃,合金的晶粒逐渐长大,合金的密度、抗弯强度随温度上升呈现出持续升高的走势,而硬度表现出先升后降的走势;当烧结温度为1380℃、保温时间为40min时,WC-14TiC-8Co超细硬质合金获得了最佳综合性能,其密度、抗弯强度和硬度值分别达到11.49g·cm^(-3)、1482MPa和92.8HRA,合金的组织为WC+(Ti,W)C+γ+少量η相,升温过程中的缺碳现象是η相形成的主要原因。

The WC-14TiC-8Co ultrafine cemented carbide was made by powder metallurgy process, and the effects of different sintering temperature on microstructure and properties of WC-14TiC-8Co ultrafine cemented carbide were studied. The results show that, with the increase of sintering temperature from 1 300℃ to 1 410℃, its grain size grows gradually, and the density and bending strength have the same increasing tendency, and the hardness rises first and then drops. When the sintering temperature is 1 380℃ and the holding time is 40 min, the best performance can be obtained. The density, bending strength and hardness are 11.49 g·cm3,1 482 MPa and 92.8 HRA, respectively, and the microstructure are WC＋ （Ti,W）C＋γ＋η （little amount）. The phenomenon of carbon-deficient in heating process is the main reason for the appearance of η phase.