稀土银合金铸态及再结晶组织的观察与分析

制备了不同稀土含量的银合金，用电子探针扫描仪观察了几种银合金的铸态组织和再结晶退火组织。研究合金的铸态组织时发现，含微量稀土(0.016％La)的银合金为固溶态，显示大晶粒组织；含0．12％RE的银合金有少量分散的球状第二相稀土化合物分布在大晶粒组织上；含1．2％RE的银合金中的稀土化合物枝晶形成连续的网状分布。稀土元素的加入，细化了冷变形再结晶组织的晶粒，经过破碎、再聚集所形成的分散的银稀土化合物第二相有效地强化了银合金，并提高合金的热稳定性。

Observation and Analysison As-cast and Re-crystallized Microstructures of Ag-RE Alloys

Silver based alloys with different contents of rare earth elements have been made. Their as cast and re crystallized microstructures have been observed by aid of SEM. It is found that the silver based alloy with trace content of RE (0 016% La) presents itself as solid solution and its grain is coarse. In the microstructure of silver based alloy with 0 12% RE, a little amounts of spherical second phase of RE compound dispersed at interfaces the coarse grains has also been observed. The dendritic RE compound in the microstructure of silver alloy with 1 2% RE creates continuous net. Addition of the RE elements makes grains of the re crystallized microstructure after cold deformation fined. The RE compound second phases having been shattered and re crystallized strengthen the silver based alloys efficiently and improve their heat stability.