Enhancing mechanical properties of Al-Mg-Si-Cu sheets by solution treatment substituting for recrystallization annealing before the final cold-rolling

A novel production method of the Al-Mg-Si-Cu cold-rolled sheets was proposed in the present work, which was characterized by solution treatment substituting for conventional intermediate recrystallization annealing before the final cold-rolling of the sheets. After further solution and peak-ageing treatment, the newly produced 6061 Al sheets exhibited markedly higher mechanical properties (ultimate tensile strength (UTS): 454 MPa, yield strength (YS): 438 MPa and elongation (El): 13%) than those of the conventionally produced ones (UTS: 384 MPa, YS: 368 MPa and El: 11%). The quantitative estimation of strengthening mechanisms indicated that the increased peak-ageing strength of the newly processed 6061 alloy sheets was mainly attributed to their high average Taylor factor value, which resulted from the P texture with high volume fraction. Furthermore, the fracture characteristics of the newly produced and peak-aged 6061 alloy sheets were dominated by dimple induced cracking accompanied by small amount of intergranular cracking.