Multi-Particle Finite Element Simulation Of Hot Pressing Of Pure WC Powders And WC-Ni Composite Powders

In this paper,MPFEM(multi-particle finite element method)is used to simulate the hot pressing(HP)process of pure tungsten carbide(WC)powders and WC-Ni composite powders.The effects of WC particle size ratio,number of particles,Ni content,pressure and temperature on the densification,internal stress/strain,stress distribution,particle deformation and void filling of pure WC sintered parts and WC-Ni alloy sintered parts are studied from the particulate scale.The densification dynamics and mechanisms are analyzed.The obtained main innovative findings are as follows.(1)In the HP process of pure WC powders,the stresses are mainly concentrated on the small particles,so the deformation of small particles is greater than that of large particles.The voids between the large particles are filled by the deformation of small particles,which results in the densification.(2)The optimal densification temperature of pure WC powders under different pressure is obtained.The results show that the higher the pressure,the lower the densification temperature.(3)In the HP process of pure WC powders,the average deformation of small particles is always greater than that of large particles,where the deformation of bottom particles is the largest,then followed by the deformation of top particles,and the deformation of middle particles is the smallest.(4)In the HP process of WC-Ni composite powders,the stresses are mainly concentrated on the harder WC particles,while the stresses on the Ni particles are relatively small.(5)When the Ni content is low,the voids between WC particles are filled by the deformation of the soft Ni particles to achieve the densification of the whole compact.When the Ni content is high,WC particles are surrounded by Ni particles,the voids between WC particles and Ni particles are filled by the deformation of the Ni particles to fulfill the densification.(6)The higher the Ni content,the lower the densification temperature required by hot pressing at the same applied pressure.