超音速电弧喷射雾化银合金熔滴的传热与冷却

Conduction of Heat and Cooling of Ag Alloy Droplets by Ultrasonic Arc Spray

对超音速电弧喷射雾化Ag—Cu共晶型和Ag—Ni、Ag—Fe偏晶型合金雾化熔滴的传热与冷却进行了分析。考虑到熔滴冷却过程中，表面热传导存在上限，内部存在一定热阻，熔滴冷却应为近似牛顿冷却方式，在前人工作基础上，对牛顿冷却方式的换热系数和冷却速率的表达公式进行了经验修正，并用其它冷却速率测量方法进行了验证；计算了Ag合金雾化熔滴的换热系数和冷却速率，结果显示，超音速电弧喷射雾化快速凝固Ag合金粉末的冷却速率达到10^-K／s，表明超音速电弧喷射雾化工艺的冷却速率比常规气雾化法高得多，是制备高性能快速凝固合金粉末的新方法。

The present paper analysed conduction of heat and cooling of eutectic Ag - Cu and monotectic Ag- Ni, Ag- Fe alloy droplets by ultrasonic arc spray. The equation on convective heat transfer coefficient and cooling rate were corrected for Ag alloy droplets in N2 gas. Calaulated results indicated that the cooling rates of Ag alloy droplets are 10^5-7K/s, which is two orders of magnitude higher than that by ultrasonic gas atomization.