快速凝固新型Au-Ag-Ge合金薄带的制备

Preparation of rapidly solidified new-type Au-Ag-Ge alloy ribbon

采用单辊快速凝固法制备了Au-19.25Ag-12.80Ge合金薄带。利用TEM方法对合金薄带的显微组织进行了观察分析,根据热传输平衡方程对快速凝固过程冷却速率进行估算。结果表明：辊面线速度在18-24 m/s范围内时,快速凝固冷却速率可达8.93×10^5-1.293×10^6K/s,随着快速凝固冷却速率的增加,合金薄带厚度有所减小;单辊快速凝固工艺的冷却速率对合金薄带的显微组织有重要影响,由于快速凝固工艺增加了材料的固溶度,减小了成分偏析,细化了晶粒,因此显微组织更加均匀细小,形成了纳米晶,快速冷却工艺在金属熔液内垂直于辊轮方向上产生的冷却速度梯度,造成了晶粒内部应力集中现象的产生。

Au-19.25Ag-12.80Ge alloy ribbons were produced by single-roller rapidly solidification method.Microstructure of the ribbons was studied by TEM,rapid solidification cooling rate was estimated according to the heat transport equilibrium equation.The results show that when the line speed of the roll surface is between 18 m/s and 24 m/s,cooling rate can get to 8.93×10^5～1.293×10^6 K/s,as the cooling rate increases,the thickness of the alloy ribbon decreases.Rapid solidification cooling rate has great impact on the microstructure of the ribbon,since rapidly solidification can increase the solid solubility,reduce the segregation and refine the grain,microstructure of the ribbon becomes much finer to form nanocrystalline.Cooling rate gradient was developed in the melted metal in the direction of vertical to the roll surface because of the rapidly solidification,which results in stress concentration in the inner crystal.