【摘要】 采用相场法模拟了表面扩散和晶界扩散机制共同作用下的四球模型和五球模型中Mo粉末压坯微粒间烧结颈长大以及孔隙的演化过程。数值模拟引入了Cahn-Hillard(CH)方程控制的相对密度场和Ginzburg-Laudau(TDGL)方程控制的长程取向场参量,并采用半隐傅立叶谱方法对上述方程进行了求解。模拟结果表明,表面扩散是Mo粉末烧结过程的主导扩散机制;压坯致密度越高,烧结完成的时间越短。更多还原

【Abstract】 The formation,growth of the sintering necks and the spheroidization of the pores,which are mainly controlled by surface diffusion and grain boundary diffusion during the sintering of Mo powder,were simulated respectively by using both four-ball and five-ball model.In the simulation process,the relative density fields governed by Cahn-Hillard equation and the long-range-order(LRO)parameter fields controlled by Ginzburg-Landau equation(TDGL)were introduced, and a semi-implicit Fourier-spectral method was used to solve the above-mentioned equations.The simulation results show that the dominant diffusion mechanism in the sintering process of Mo powder is surface diffusion,and the higher the density of green compact,the shorter the sintering time.更多还原