熔体过热处理影响合金凝固特性的机制

Mechanism of the Effect of Melt Superheating on the Solidification Behavior of Alloy

对熔体过热处理影响合金液形核温度、结晶潜热和结晶相生长特性的机制进行了理论研究.从理论上得到了铝熔体中最大尺寸原子团的原子数与熔体温度、合金结晶潜热和合金中结晶相生长特性因子与合金液性质之间的理论关系式,根据得到的理论关系式可预测熔体过热温度对金属液的形核温度、合金液的结晶潜热及合金中结晶相生长特性因子影响趋势.由文中理论关系预测出Al-Si合金的形核过冷度随熔体过热温度的升高而增大、结晶潜热随熔体过热温度的升高而减小、结晶相生长特性因子随熔体过热温度的升高而减小.

Mechanisms of effects of melt superheating on the nucleation temperature, the latent heat of crystallization and the behavior of crystal growth of alloy have been studied theoretically. Theoretical formulae between the cluster size of metal melt and the melt temperature, between the latent heat of crystallization and the property of alloy melt and between the behavior of crystal growth and the property of alloy have been developed. In terms of these theoretical formulae, the dependent tendency of the nucleation temperature, the latent heat of crystallization and the behavior of crystal growth of alloy melt on melt temperature can be predicted. The predicted results about Al-Si alloy show that the nucleation increases with increasing the melt superheating, the latent heat of crystallization and the behavior of crystal growth decrease with increasing the melt superheating ,which are in agreement with the experiential results.