Al-Ni-Y三元合金定向凝固共晶生长机制  

Eutectic Growth Mechanism in the Directionally Solidifidied Al-Ni-Y Ternary Alloy

作　　者：刘普祥 徐瑞[1] 

机构地区：[1]燕山大学亚稳材料制备技术与科学国家重点实验室,河北秦皇岛066004

出　　处：《稀有金属材料与工程》2013年第S2期354-358,共5页Rare Metal Materials and Engineering

摘　　要：在5 K/mm温度梯度下,以5,10,15 mm/min的下拉速率,对成分为Al-1.0Ni-3.0Y(at%)三元共晶合金进行下拉定向凝固,探讨不同下拉速率下各组成相及共晶团体积分数变化规律。通过光学显微镜(OM)、扫描电子显微镜(SEM)观察组织,并利用扫描电子显微镜观察了深腐蚀后组织的立体形貌,分析其共晶生长机制。研究表明,合金有两种共晶,其中Al23Ni6Y4相与?-Al相形成规则层片状共晶组织,两相共生生长,而Al3Y相与?-Al相形成菊花状共晶组织,Al3Y相为领先相,以其择优取向优先生长。In order to research the changes of the volume fractions of each phase and eutectic structure under different pulling rates,the upward directional solidification of the alloy with chemical composition of Al-1.0 Ni-3.0 Y(at%) was carried out at 5,10,15 mm/min pulling-down rates,under the constant temperature gradient of 5 K/mm.The microstructure of the directionally solidified alloy and the stereoscopic topography of eutectic structure after deep corrosion was observed by the optical microscope(OM) and the scanning electron microscope(SEM),and the mechanism of its eutectic growth was analyzed.The results show that there are two kinds of eutectic structure in the alloy.The regular lamellar eutectic structure consisted of Al23Ni6Y4 phase and α-Al phase are grown coupled and the chrysanthemum-like eutectic structure is consisted of the Al3Y phase and α-Al phase grown with the Al3Y as a leading phase in its preferred orientation.

关 键 词：定向凝固 共晶生长机制 体积分数 立体形貌 

分 类 号：TG111.4[金属学及工艺—物理冶金]