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采用落管无容器处理技术实现了直径为60~800 mm的Ag60Sb34Cu6三元合金液滴的快速凝固, 对其凝固机理进行了理论探索. 随着液滴尺寸的减小, 冷却速率从57 K/s增大至5.8 104 K/s, 最大过冷度达180 K(0.23TL), 初生e(Ag3Sb)枝晶发生了显著细化, 直至形成均匀的等轴晶. 实验结果表明, 深过冷条件使得(e + Ag)二相共晶在小液滴中难以生成, 同时初生e相中Ag的固溶度随液滴过冷度的增大显著增大. 根据差热分析与晶体生长形态, 提出了合金液滴在不同过冷度下的两种凝固方式.
The rapid solidification of Ag60Sb34Cu6 ternary alloy droplets with a diameter of 60 ~ 800 mm was achieved by means of dropless tubeless vessel processing technique, and the solidification mechanism was theoretically probed.With the decrease of droplet size, the cooling rate decreased from 57 K / s increased to 5.8 104 K / s and the maximum undercooling reached 180 K (0.23 TL). The dendrites of primary e (Ag3Sb) thinned significantly until uniform equiaxed grains were formed. The experimental results showed that the supercooling Under the conditions, the (e + Ag) two-phase eutectic is hard to be formed in the small droplets and the solid solubility of the primary e phase increases with the increase of the degree of undercooling.According to the differential thermal analysis and crystal growth morphology , Proposed two kinds of solidification mode of alloy droplets under different undercooling.