Al-Y包晶合金非平衡凝固过程及组织特征-中国材料进展

文章信息/Info

Title:: Investigation of the non-equilibrium solidification and microstructures of Al-Y Peritectic Alloys

Author(s):: WANG Liang; ZHANG Yanning; LUO Liangshun; Liu Dongmei; SU Yanqing*; GUO Jingjie; FU Hengzhi; National Key Laboratory for Precision Hot Processing of Metals, School of Materials Science and Engineering, Harbin Institute of Technology

摘要:: 包晶凝固过程中小平面-小平面两相复相生长方式是凝固领域研究的一个热点。本文以初生相和包晶相都是严格计量比金属间化合物的Al-Y包晶合金作为研究对象，利用DSC热分析技术，严格控制冷却速度，获得不同凝固条件的非平衡凝固试样，研究了两相为小平面相的Al-Y包晶合金的凝固行为。发现小平面-小平面包晶系合金包晶凝固过程中，非平衡凝固特性及宏观偏析特点比非小平面包晶系更加明显。凝固特征温度与平衡相图偏差明显，包晶反应温度和包晶相直接凝固温度都远高于平衡相图给定的值，最后得到的凝固组织也与平衡相图存在显著差异。

Abstract:: Facted-facted two-phase peritectic solidification behaviors are one of the hotspot of solidification field. In this study, Al-Y peritectic alloys, in which the peritetic phase and primary phase are intermetallic compound with stoichiometric composition, have been chosen for investigation. Using differential scanning calorimetry (DSC), obtained the heating and cooling curves of Al-Y alloys at different strictly controlled cooling rates. Concurrently, the non-equilibrium solidification microstructures were produced. Based on these experimental results, we found that the non-equilibrium solidification characteristics and characteristics of macrosegregation of the facted-facted peritectic alloy solidification process are more obvious than non-faceted peritectic alloys. The solidification characteristic temperature is greatly different to the equilibrium phase diagram. The peritectic reaction temperature and the nucleation temperature of peritectic phase from the melt during cooling are higher than that of the equilibrium phase diagram. The resulting solidification microstructures are also significant differences with the equilibrium phase diagram.