Mechanical Properties and Microstructure of Thin-Walled Al-Cu Alloy Casting

This study aimed to investigate the tensile properties and microstructure of Al-Cu alloy casting with a dimension of ∅500 mm × 700 mm and a 5mm-thick wall at room temperature and 200°C. The results indicated that the strength and elongation of Al-Cu alloy casting at room temperature were excellent, exceeding 425 MPa and 8%, respectively. Such a good performance was attributed to the tiny equiaxed grains. However, the occurrence of acicular θ phase distributed around the α-Al matrix grains was disadvantageous to strength and especially to elongation. Moreover, no dynamic recrystallization was observed in the tensile tests at 200°C. Besides, numerous dimples were found in the fracture morphology, which were beneficial to the elongation.