摘要
本文采用经典硬质合金制备方法,制备不同粘结相含量的钨钴硬质合金,利用真空气淬工艺在不同热处理温度下对所制合金进行淬火处理,根据试验结果探讨硬质合金淬火孔隙的形成机理并分析其影响因素。研究表明,钴含量和淬火温度均对合金淬火孔隙形成具有显著影响。当合金中钴的质量分数为20%和25%时,淬火导致合金中出现孔隙缺陷。孔隙数量随着淬火温度的升高显著增加,淬火温度超过1 200℃时,合金孔隙度可由A02B00C00转变为A08B00C00。当钴的质量分数低于15%或达到30%时,淬火热处理不会导致合金出现淬火孔隙。淬火孔隙产生根本原因是Co的热膨胀系数是WC的3倍多,淬火冷却时产生的热应力大于WC/Co界面结合力,造成界面处开裂。
WC-Co cemented carbide with different content of binding phase was prepared by traditional method. The cemented carbide was quenched in vacuum at different temperature. The formation mechanism of the pores in the cemented carbide caused by quenching and the influence factors were discussed. The results show that the Co content and the quenching temperature have significant influence on the formation of the pores. The cemented carbide with Co content of 25% and 20% appears pores after quenching. The amount of the pore increases with the increase of quenching temperature. When the quenching temperature exceeds 1 200 ℃, the porosity of the cemented carbide is transformed from A02B00C00 to A08B00C00. When the Co content is below 15% or up to 30%, no pores come into being during quenching. The fundamental reason of the pores resulted from quenching is that the thermal expansion coefficient of Co is more than 3 times compared with that of WC. The thermal stress caused by quenching is greater than WC/Co interfaeial strength, which results in the cracks at the interfaces.
出处
《硬质合金》
CAS
2016年第3期176-180,193,共6页
Cemented Carbides
