Ti(C,N)含量和烧结温度对梯度硬质合金脱β层厚度的影响

Effects of Ti(C,N)content and sintering temperature on the thickness ofβ-free layer of graded cemented carbides

以Ti(C,N)为N源,在脱氮气氛下烧结制备WC-TiC-Ti(C,N)-TaC-NbC-Co硬质合金,研究Ti(C,N)含量和烧结温度对脱β层厚度及合金微观组织与性能的影响。结果表明:随Ti(C,N)的质量分数从0.5%增加到1.5%,脱β层厚度持续增大。随烧结温度升高,脱β层厚度增大,增大的幅度随Ti(C,N)含量增加而增大。合金的密度、硬度和矫顽磁力不受Ti(C,N)含量的影响,但随烧结温度升高,合金的硬度降低、矫顽磁力变小、WC平均晶粒尺寸增大且直边化。脱β层中无明显的WC晶粒异常长大现象,脱β层厚度由Ti的扩散和N含量决定。

WC-TiC-Ti(C,N)-TaC-NbC-Co cemented carbide was prepared in denitrification atmosphere with Ti(C,N)as N source.The effects of Ti(C,N)content and sintering temperature on the thickness ofβ-free layer,properties and microstructure of the cemented carbides were investigated.The results show that the thickness ofβ-free layer increases with increasing mass fraction of Ti(C,N)from 0.5%to 1.5%.With the increase of sintering temperature,the thickness ofβ-free layer increases,and the increment increases with increasing Ti(C,N)content.The density,hardness and coercivity of the alloy are not affected by Ti(C,N)content.However,with the increase of sintering temperature,the hardness decreases,the coercivity decreases,and the average grain size of WC increases and becomes straight.There is no obvious abnormal growth of WC grains in theβ-free layer,and the thickness ofβ-free layer is determined by the diffusion of Ti and the content of N.