A356-RE合金中稀土铝化合物/初生α相界面二维错配度的计算及验证  

Calculation of Planar Disregistries between Compounds of Rare Earth-Al and Primary α Phase in A356-RE Alloy and Its Verification

作　　者：刘政[1] 谌庆春[1] 郭颂[1] 刘骏义 胡钱钱[1] 

机构地区：[1]江西理工大学,江西赣州341000

出　　处：《稀有金属材料与工程》2015年第4期859-865,共7页Rare Metal Materials and Engineering

基　　金：国家自然科学基金项目(51361012);江西省自然科学基金项目(20114bab206014);江西省教育厅科技落地计划项目(KJLD12070)

摘　　要：计算了稀土铝化合物/初生α相界面的二维点阵错配度,结果显示稀土-铝共晶反应产物:稀土铝化合物可作为初生α相的异质形核质点而起到细化晶粒的作用,并通过实验证明计算结果:选用Ce、Y、Gd添加至A356合金中并分别在稀土-铝共晶温度上、下保温若干时间,利用图像分析工具得到各A356-RE合金中初生α相的平均晶粒尺寸和形状因子。实验结果表明A356-RE合金在Al-RE共晶温度之下保温,可获得细小的球状初生α相,这与稀土铝化合物与初生α相的二维点阵错配度在15%以内、异质形核质点的大幅增加相关,且二维错配度可表征其细化A356合金初生α相的能力。Planar disregistries between various RE-A1 compounds and primary a phase during the liquid A356 alloy solidification were calculated. And results show that the RE-A1 eutectic reaction products could be used as the heterogeneous nucleation＇s centroids of primary a phase and play the role of grain refinement. Several experiments were designed to prove the calculation results as following： Ce, Y and Gd were selected as the additives in A356 alloy and the alloy was isothermally held 10 ℃ above and below the RE-A1 eutectic temperature for 2 min. The average grain size and the shape factor of primary a phase in A356-RE alloy were calculated by image analysis tools. The results indicate that the fine primary a phase with globular-like could be obtained when A356-RE alloy is isothermally held below the eutectic temperature. The planar disregistry between RE-A1 compounds and primary a phases less than 15% as well as the significant increase of heterogeneous nucleation centroids are the main reasons for refining. The planar disregistry could characterize the ability of refining primary a phase by RE in A356 alloy.

关 键 词：A356铝合金 稀土 共晶反应 二维错配度 半固态 

分 类 号：O641.4[理学—物理化学]