摘要
Al-Cu-Mg-Ag alloys have become a research hotspot because of its good heat resistance.Its excellent mechanical properties are inseparable from the regulation of the structure by researchers.The method of material structure simulation has become more and more perfect.This study employs numerical simulation to investigate the microstructure evolution of Al-Cu-Mg-Ag alloys during solidification with the aim of controlling its structure.The size distribution of Ti-containing particles in an Al-Ti-B master alloy was characterized via microstructure observation,serving as a basis for optimizing the nucleation density parameters for particles of varying radii in the phase field model.The addition of refiner inhibited the growth of dendrites and no longer produced coarse dendrites.With the increase of refiner,the grains gradually tended to form cellular morphology.The refined grains were about 100μm in size.Experimental validation of the simulated as-cast grain morphology was conducted.The samples were observed by metallographic microscope and scanning electron microscope.The addition of refiner had a significant effect on the refinement of the alloy,and the average grain size after refinement was also about 100μm.At the same time,the XRD phase identification of the alloy was carried out.The observation of the microstructure morphology under the scanning electron microscope showed that the precipitated phase was mainly concentrated on the grain boundary.The Al_(2)Cu accounted for about 5%,and the matrix phase FCC accounted for about 95%,which also corresponded well with the simulation results.
Al-Cu-Mg-Ag合金因具有良好的耐热性而成为研究热点。其优异的力学性能离不开研究人员对结构的调控,材料结构模拟的方法日趋完善。本研究通过数值模拟研究Al-Cu-Mg-Ag合金的组织演变过程,进而对其组织进行调控。首先,通过显微组织观察统计了Al-Ti-B中间合金中含Ti颗粒的尺寸比例,优化了相场模型中不同半径形核质点的形核密度参数。细化剂的加入抑制了枝晶的生长,不再产生粗大的枝晶。随着细化剂的增加,晶粒逐渐趋于形成胞状形貌。细化后的晶粒约为100μm。最后,通过实验对铸态晶粒形貌进行了验证,采用金相显微镜和扫描电子显微镜对试样进行观察。细化剂的加入对合金的细化效果有显著影响,细化后的晶粒尺寸也在100μm左右。同时,对合金进行了X射线衍射物相鉴定。扫描电镜下的组织形貌观察表明,析出相主要集中在晶界上,Al_(2)Cu约占5%,基体相面心立方(FCC)约占95%,与模拟结果吻合较好。
出处
《材料科学与工程学报》
北大核心
2025年第4期513-519,524,共8页
Journal of Materials Science and Engineering
作者简介
ZHU Shiqing(2000-),Master,Research direction:aluminum alloy solidification.E-mail:zhushiqing316@163.com;Corresponding author:ZHANG Hong(1974-),Professor,Doctor,Research direction:material processing and forming.E-mail:zhanghong@ustb.edu.cn。
