摘要
采用液-固复合铸造技术制备未经表面处理和经热浸镀铝表面处理的AZ91D/0Cr19Ni9双金属复合材料,研究铝涂层对AZ91D/0Cr19Ni9界面显微组织和力学性能的影响。结果表明:镁合金和裸钢0Cr19Ni9之间为机械结合,结合界面处存在一缝隙;而镁合金AZ91D和镀铝钢0Cr19Ni9之间形成冶金结合,且镁合金AZ91D/镀铝钢0Cr19Ni9界面可以分为两个不同的金属间化合物层:层Ⅰ主要由α-Mg+β-Mg_(17)Al_(12)共晶组织和少量的MgAl_2O_4相组成,层Ⅱ主要由Fe_2Al_5金属间化合物组成。此外,结合界面的硬度明显高于镁合金基体AZ91D的硬度,层Ⅰ和层Ⅱ的平均硬度分别为HV158和HV493。镁合金AZ91D/镀铝钢0Cr19Ni9界面的剪切强度高于镁合金AZ91D/裸钢0Cr19Ni9界面的剪切强度,这证明在液-固复合铸造过程中铝涂层能提高镁合金AZ91D和钢0Cr19Ni9之间的结合强度。
The liquid-solid compound casting technology was used to produce the AZ91D/0Cr19Ni9 bimetal composite without and with hot dipping aluminium, respectively. The influences of Al coating on microstructures and mechanical properties of AZ91D/0Cr19Ni9 interface were investigated. The results showed that the mechanical bonding was obtained between AZ91D and bare steel 0Cr19Ni9 where a gap existed at the interface; the metallurgical bonding was formed between AZ91D and Al-coated 0Cr19Ni9, which could be divided into two different intermetallic layers: layer Ⅰ was mainly composed of α-Mg+β-Mg17Al12 eutectic structure and a small amount of MgAl2O4, and layer Ⅱ mainly comprised of Fe2Al5 intermetallic compound. Furthermore, the hardness value of interface was obviously higher than that of AZ91D matrix, and the average hardness values of layers Ⅰ and Ⅱ were HV 158 and HV 493, respectively. The shear strength of AZ91D/Al-coated 0Cr19Ni9 interface was higher than that of AZ91D/bare 0Cr19Ni9 interface, which confirmed that Al coating could improve the adhesive strength between AZ91D and 0Cr19Ni9 during liquid-solid compound casting process.
作者
赵建华
赵文群
屈伸
张彦青
Jian-hua ZHAO;Wen-qun ZHAO;Shen QU;Yan-qing ZHANG(State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044, China;College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China)
基金
Project(cstc2015yykfC0001)supported by the National Engineering Research Centre for Magnesium Alloys,China
Project supported by State Key Laboratory of Mechanical Transmission of Chongqing University,China
