Optimization of mechanical properties using D-optimal factorial design of experiment: Electromagnetic stir casting process of A357-SiC nanocomposite  

运用D实验设计优化电磁搅拌铸造A357-SiC纳米复合材料的力学性能

作　　者：Reza MOHAMMADI BADIZI Amir PARIZAD Mohsen ASKARI-PAYKANI Hamid Reza SHAHVERDI Reza MOHAMMADI BADIZI;Amir PARIZAD;Mohsen ASKARI-PAYKANI;Hamid Reza SHAHVERDI(Department of Materials Engineering,Tarbiat Modares University,P.O.Box 14115-143,Tehran,Iran)

机构地区：[1]Department of Materials Engineering,Tarbiat Modares University,P.O.Box 14115-143,Tehran,Iran

出　　处：《Transactions of Nonferrous Metals Society of China》2020年第5期1183-1194,共12页中国有色金属学报（英文版）

摘　　要：Electromagnetic stir casting process of A357-Si C nanocomposite was discussed using the D-optimal design of experiment(DODOE) method. As the main objective, nine random experiments obtained by DX-7 software were performed. By this method, A357-Si C nanocomposites with 0.5, 1.0 and 1.5 wt.% Si C were fabricated at three different frequencies(10, 35 and 60 Hz) in the experimental stage. The microstructural evolution was characterized by scanning electron and optical microscopes, and the mechanical properties were investigated using hardness and roomtemperature uniaxial tensile tests. The results showed that the homogeneous distribution of Si C nanoparticles leads to the microstructure evolution from dendritic to non-dendritic form and a reduction of size by 73.9%. Additionally, based on DODOE, F-values of 44.80 and 179.64 were achieved for yield stress(YS) and ultimate tensile strength(UTS), respectively, implying that the model is significant and the variables(Si C fraction and stirring frequency) were appropriately selected. The optimum values of the Si C fraction and stirring frequency were found to be 1.5 wt.% and 60 Hz, respectively. In this case, YS and UTS for A357-Si C nanocomposites were obtained to be 120 and 188 MPa(57.7% and 57.9 % increase compared with those of the as-cast sample), respectively.采用D实验优化设计(DODOE)方法,对A357-SiC纳米复合材料的电磁搅拌铸造工艺进行研究。以DX-7软件获得的9个随机实验设计方案为主要目标,在3种不同的频率(10、35和60 Hz)下制备不同SiC含量(0.5%、1.0%和1.5%,质量分数)的A357-SiC纳米复合材料。用扫描电镜和光学显微镜对其显微组织演变进行表征,并通过硬度和室温单轴拉伸试验对其力学性能进行研究。结果表明,SiC纳米颗粒的均匀分布使材料的显微组织由枝晶向非枝晶态演化,晶粒尺寸减小73.9%。此外,基于DODOE获得的屈服强度和极限抗拉强度的F值分别为44.80和179.64,表明该模型具有显著性,变量(SiC含量和搅拌频率)选取合适。结果表明,最佳搅拌频率为60 Hz,最佳SiC含量为1.5%(质量分数),在此条件下,A357-SiC纳米复合材料的屈服强度和极限抗拉强度分别为120和188 MPa,比铸态试样的分别提高57.7%和57.9%。

关 键 词：A357 alloy electromagnetic stir casting Si C nanoparticles mechanical properties D-optimal design of experiments 

分 类 号：TG292[金属学及工艺—铸造] TB333[一般工业技术—材料科学与工程]