梯度硬质合金梯度层形成的计算机模拟及验证

Computer simulation of gradient zone formation in cemented carbides and its verification

结合相图热力学计算,使用DICTRA软件计算模拟Co-W-Ti-C-N、Co-W-Ti-Nb-C-N和Co-W-Ti-Ta-C-N体系梯度硬质合金梯度层形成过程,对比计算模拟和实测的梯度硬质合金中Co含量的距离变化曲线。通过分析各相体积分数及组元成分随距离的分布研究烧结时间、烧结温度、Co含量和Ti含量对梯度层厚度的影响。结果表明:计算模拟与实验数据吻合较好。延长烧结时间、升高烧结温度和增加Co含量均会促进梯度层厚度的增加,而增加Ti含量则会抑制梯度层厚度的增加。

The gradient zone formation in Co-W-Ti-C-N, Co-W-Ti-Nb-C-N and Co-W-Ti-Ta-C-N cemented carbides was simulated by using the DICTRA software package in conjunction with thermodynamic calculations. Simulated elemental concentration profiles for Co were compared with the experimental results. Taking into account the volume fractions of different phases and elemental concentration profiles, the effects of sintering time, sintering temperature, as well as the contents of Co and Ti on gradient zone formation, were investigated. The results show that the simulated results agree reasonably with the experimental data. The long sintering time, high sintering temperature and large content of Co increase the thickness of the gradient zone, but the high content of Ti restrains the thickness of gradient zone increasing.