Simulation and experimental verification of interfacial interactions in compound squeeze cast Al/Al-Cu macrocomposite bimetal
(1. Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran;
2. Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran)
2. Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran)
Abstract: The objective of this work was to investigate the thermal and mechanical interactions between the two components of a compound squeeze cast macrocomposite bimetal. First, an Al/Al-4.5wt.%Cu macrocomposite bimetal was fabricated by compound squeeze casting process. Then, heat transfer, solidification and distribution of the generated stresses along the interface region of the bimetal were analyzed using Thermo-Calc, ProCAST and ANSYS softwares, and structure, copper distribution and microhardness changes across the interface of the bimetal were studied. The results showed no noticeable change in the structure of the Al-4.5wt.%Cu insert and no obvious micromixing and diffusion of copper across the interface. Simulation results were in good agreement with the experimental ones only when an equivalent oxide layer at the interface was defined and its effect on heat transfer was considered. This layer caused up to 50% decrease in local liquid fraction formed on the surface of the insert. Simulation of the generated stresses showed a uniformly distributed stress along the interface which was significantly lower than the compressive strength of the oxide layer, resulting in its good stability during the fabrication process. It was postulated that this continuous oxide layer not only acted as a thermal barrier but prevented the direct metal-metal contact along the interface as well.
Key words: Al/Al-Cu macrocomposite; bimetal; compound squeeze casting; simulation; interface; stress