镍基单晶高温合金定向凝固微观组织模拟及试验验证  

Microstructure Simulation and Experimental Validation of Ni-based Superalloy during Directional Solidification

作　　者：夏鹄翔 杨聪 许庆彦 Xia Huxiang;Yang Cong;Xu Qingyan(Key Laboratory of Advanced Forming Manufacturing, Ministry of Education,School of Materials Science and Engineering, Tsinghua University)

机构地区：[1]清华大学材料学院先进成形制造教育部重点实验室

出　　处：《特种铸造及有色合金》2021年第11期1334-1338,共5页Special Casting & Nonferrous Alloys

基　　金：国家科技重大专项资助项目(2017-Ⅵ-0003-0073,2017-Ⅶ-0008-0101)。

摘　　要：针对定向凝固过程,建立了镍基单晶高温合金宏观温度场计算模型和微观组织相场计算模型。模拟了定向凝固过程中高温合金单晶试棒的温度场变化,并基于温度场结果进一步模拟了微观组织生长情况。将模拟结果与试验结果进行对比,二者较为一致,验证了计算模型的准确性。结果表明,定向凝固单晶试棒不同区域的枝晶形貌有较显著差异,冷却速度较快的区域一次枝晶臂间距较小;冷却速度较慢的区域枝晶粗大,具有发达的一次枝晶臂和二次枝晶臂,且一次枝晶臂间距较大。The calculation models of macroscopic temperature field and microstructure phase field of Ni-based single crystal superalloy during directional solidification were established.The temperature fileld change of single crystal rod during directional solidification was simulated.Based on the macroscopic temperature field,the growth of microstructure was simulated.The microstructure of nickel-base single crystal superalloy was compared with the simulation results to verify the accuracy of the calculation model.Both the simulation and experimental results indicate that the dendrite morphology in different regions of single crystal rod after directional solidification has significant difference.The dendrite under high cooling rate presents small primary dendrite arm spacing,while that under low cooling rate is quite coarse,with well-developed primary and secondary dendrite arm as well as large primary dendrite arm spacing.

关 键 词：高温合金 定向凝固 数值模拟 相场 

分 类 号：TG132.32[一般工业技术—材料科学与工程]