提高复合挤压铸造Al/Al−Cu双金属宏观复合材料界面结合的新方法

摘要

A facile and innovative method to improve bonding between the two parts of compound squeeze cast Al/Al?4.5wt.％Cu macrocomposite bimetals was developed and its effects on microstructure and mechanical properties of the bimetal were investigated. A special concentric groove pattern was machined on the top surface of the insert (squeeze cast Al?4.5wt.％Cu) and its effects on heat transfer, solidification and distribution of generated stresses along the interface region of the bimetal components were simulated using ProCAST and ANSYS softwares and experimentally verified. Simulation results indicated complete melting of the tips of the surface grooves and local generation of large stress gradient fields along the interface. These are believed to result in rupture of the insert interfacial aluminum oxide layer facilitating diffusion bonding of the bimetal components. Microstructural evaluations confirmed formation of an evident transition zone along the interface region of the bimetal. Average thickness of the transition zone and tensile strength of the bimetal were significantly increased to about 375 μm and 54 MPa, respectively, by applying the surface pattern. The proposed method is an affordable and promising approach for compound squeeze casting of Al?Al macrocomposite bimetals without resort to any prior cost and time intensive chemical or coating treatments of the solid insert.%开发一种简便的提高复合挤压铸造Al/Al?4.5wt.％Cu双金属复合材料界面结合的新方法,并研究该方法对此双金属的显微组织和力学性能的影响.在挤压铸造Al?4.5wt.％Cu的内表面机加工一种特殊的同心槽图案,利用ProCAST和ANSYS软件对双金属构件界面区域的传热、凝固和产生的应力分布进行数值模拟,并进行实验验证.模拟结果表明,表面沟槽尖端完全熔化,沿界面产生较大的局部应力梯度场,这会导致插入界面的氧化铝层破裂,促进双金属组分的扩散结合.显微组织表征证实双金属界面存在明显的过渡区.通过加工表面图案,双金属的平均过渡区厚度和抗拉强度分别显著增加到375μm和54 MPa.因此,该方法是一种经济可行的复合挤压铸造铝?铝宏观复合双金属的方法,不需要提前对固体镶块进行任何成本和时间密集型的化学或涂层处理.