Al-Mg粉末烧结过程中晶界扩散的原位观察

In-situ Observation of Sintering Process of Al and Mg Binary Alloys System

利用光学高温金相显微镜对Al 1 0Mg二元纯金属粉末体系的烧结过程进行原位观察 ,发现在镁颗粒内部晶界优先熔化 ,这是由于铝沿镁晶界的扩散系数远高于晶内扩散系数 ,在镁的晶界优先满足共晶的浓度条件而熔化造成的 ,从而直接证实晶界确是元素扩散的一条快速通道。

It is well-known that grain boundary diffusion is a short circuit diffusion. But this has not been proved by direct observation proofs. A high temperature optical microscope was used to in-situ investigate the sintering process of Al-10Mg binary system. It is found that the melting occurs at grain boundary ahead of grain melting, which is caused by the diffusion rate of aluminum along magnesium grain boundary faster than that in grain. It is proved that grain boundary is a fast diffusion channel of atoms.