浇注温度对Al-5Zr中间合金初生Al_3Zr相影响机理研究

基于"固体与分子经验电子理论"(EET),计算了Al-5Zr中间合金熔体的价电子结构参数统计值,构建了高温与低温浇注时铝锆熔体中Al3Zr相的结晶过程模型,研究了浇注温度对Al-5Zr中间合金初生Al3Zr相形貌、尺寸及数量的影响。结果表明:随着浇注温度的升高,Al3Zr晶体的形貌由小块状逐渐长成长条状,平均尺寸增加,数量减少;当温度低于1000℃时,数量较多、A E?值较大的Al-Zr、Zr-Zr原子团簇不断聚集形核,最终形成大量小块状Al3Zr晶体;温度高于1000℃时,数量少、A E?值较大的Zr-Zr原子团簇聚集形核,从而形成数量较少的长条状Al3Zr晶体。建立的模型与实验结果符合较好。

Effect of Pouring Temperature on the Primary Al3Zr Phase in Al-5Zr Master Alloy

Based on the empirical electron theory of solids and molecules (EET), the statistical values of valence electron structure parameters of Al-5Zr master alloy melt were calculated, and the crystallization process models of the Al3Zr phase in the Al-5Zr melt were built at high and low pouring temperatures. The effect of pouring temperature on the morphology, size and the amount of primary Al3Zr phase during the solidification of Al-5Zr master alloys was investigated. The results show that the morphologies change from small blocks to long needles, the average size increases and the amount decreases for the Al3Zr crystals with the increase of pouring temperature. When the pouring temperature is below 1000 °C, the Al-Zr and Zr-Zr clusters with larger quantities and larger gather, nucleate and finally form a large number of small blocky Al3Zr crystals; when the pouring temperature is above 1000 °C, the Zr-Zr clusters with fewer quantities and largeraggregate, nucleate and ultimately form a small number of Al3Zr crystals with long needle shape. The established models agree well with the experimental results