High strength and ductility aluminium alloy processed by high pressure die casting

A high strength (Yield strength >= 320 MPa) and high ductility (Tensile elongation >= 10%) die-cast aluminium alloy was first developed. The AlSiCuMgMn alloy processed by high pressure die casting can provide the high yield strength of 321 MPa, the high ultimate tensile strength of 425 MPa and the high ductility of 11.3%, after solution treated at 510 degrees C for 30 min and aged at 170 degrees C for 12 h. The alloy demonstrated 150% increase in ductility over the reported most advanced die-cast aluminium alloy, also comparable tensile properties to the 6000 series wrought aluminium alloys but with much lower manufacturing cost. The as-cast microstructure of the alloy mainly contained the primary alpha(1)-Al phase solidified in the shot sleeve, the secondary alpha(2)-Al phase solidified in the die, the Al-Si eutectic phase and the intermetallic phases Q-Al5Cu2Mg8Si6 and theta-Al2Cu. The intermetallic phases Q and theta were dissolved into the alpha-Al matrix during solution. Nanoscale precipitates Q' and theta' were precipitated from the alpha-Al matrix for the strengthening of the alloy through ageing treatment. Multiple effects resulted in the high ductility of the alloy. (C) 2018 Elsevier B.V. All rights reserved.