6 . the melting of the grain boundary is the reason of the semi - solid grain globalization , and its control factors were the atomic diffusion velocity and the liquid - solid interface curvature 6 、半固态晶粒球状化的基本原因是晶界熔化,其控制因素是因液界面处原子扩散迁移的速度和界面曲率。
The samples were welded at 750 , 800 , 850 and 900 . the diffusion coefficients ( d ) of cu and ni at interface increased with the increase of welding temperature . and comparing with radiation heating , atom diffusion velocity at interface quickened 其它条件相同时,分别在750 、 800 、 850 、 900的温度下采用脉冲大电流加热连接cu和ni片状材料,结果表明接触面处cu和ni的扩散系数随温度升高而增大。
Upon the foundation of contracted - ball , function equations of conversion rates of grains and time are deduced . it is brought forward that the conversion rates of grains rely on reaction velocity at interface and diffusion velocity in reacted layer and at the same time relate to reaction process 建立了粉粒反应的缩球模型,推导了颗粒反应转换率随时间的变化规律,提出了颗粒反应转换率取决于界面化学反应速率和已反应层内的扩散速率两个因素并与反应进程有关。