CAJ | 학술논문

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。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，相对于相图是在“过热”条件下发生的，而固溶体型包晶合金一般是在“过冷”条件下发生的。包晶转变过程非常微弱，致使初生相残留量远高于平衡相图。即使对于过包晶成分的合金，其凝固组织中仍存在大量的共晶凝固组织，最终得到的凝固组织与平衡相图存在显著差异。
포정응고과정중소평면-소평면량상복상생장방식시응고영역연구적일개열점。이초생상화포정상도시엄격계량비금속간화합물적Al-Y포정합금작위연구대상，이용 DSC열분석기술，엄격공제냉각속도，획득불동응고조건적비평형응고시양，연구료량상위소평면상적Al-Y포정합금적응고행위。발현소평면-소평면포정계합금포정응고과정중，비평형응고특성급굉관편석특점비비소평면포정계경가명현。응고특정온도여평형상도편차명현，포정반응온도화포정상직접응고온도도원고우평형상도급정적치，상대우상도시재“과열”조건하발생적，이고용체형포정합금일반시재“과랭”조건하발생적。포정전변과정비상미약，치사초생상잔류량원고우평형상도。즉사대우과포정성분적합금，기응고조직중잉존재대량적공정응고조직，최종득도적응고조직여평형상도존재현저차이。
Facted-facted two-phase peritectic solidification behaviors are one of the hotspots of solidification field .In this study, Al-Y peritectic alloys, in which the peritetic phase and primary phase are intermetallic compound with stoichiomet-ric composition, have been chosen for investigation.Using differential scanning calorimetry ( DSC) , the heating and cool-ing curves of Al-Y alloys at different strictly controlled cooling rates were obtained .Concurrently, the non-equilibrium so-lidification microstructures were produced .Based on these experimental results , we found that the non-equilibrium solidifi-cation characteristics and characteristics of macrosegregation of the facted-facted peritectic alloy during solidification process are more obvious than non-faceted peritectic alloys.The solidification characteristic temperature is greatly different from 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 .This phenomenon can be called as “su-perheating” compared to the “undercooling” needed for solid solution phase peritectic systems.The peritectic transforma-tion is very weak and more primary phase was remained compared to the diagram .Even for the hypo-peritectic alloy, there are a lot of eutectic phases produced from the remaining liquid between the peritectic phase .The resulting solidification microstructures are significantly different with the equilibrium phase diagram .