烧结理论进展——2.烧结初期多种扩散机制耦合作用的烧结模型

在恒体积条件下给出了多种扩散机制耦合作用两球单元烧结模型的推导过程,编制了相应的计算软件,计算了铜在不同的粒度、温度、时间条件下的颈长方程和对心收缩方程。结果表明:在相同条件下,多机制综合作用颈长方程略高于表面扩散机制单独起作用的颈长方程;多机制综合作用的对心收缩小于只考虑晶界扩散和体积扩散的对心收缩。颈长方程的时间指数随时间的增加而变小。在不同烧结条件下各种机制对颈部物质的贡献存在很大差别。加热速率影响颗粒的对心收缩,在相同烧结时间内,加热速率越低,烧结收缩量越大。压密度越高,在烧结初期颗粒的颈长速率和收缩速率越低。

COUPLING MODEL OF MULTIPLE SINTERING MECHANISMS FOR THE INITIAL STAGE SINTERING

The derivation and simulation of two-sphere model coupling with multiPle diffusion mechanisms have been conducted under the condition of volume conservation. The neck growth equation and shrinkage for copper have been computed with different sintering time, temperature and particle size. The neck equation given by the coupling model is greater than that given by surface diffusion modal. The shrinkage given by coupling model is less than that given by the model only considering grain boundary diffusion and volume diffusion. The simulation indicated that time index of neck growth equation becomes lower with the increase of sintering time. The contribution to neck growth from each mechanism has been given under different conditions. The Paper indicated that slow heating rate gives more shrinkage and bigger initial contact radius gives less shrinkage