Strengthening mechanism of Sr element on 6063 Al alloys

Abstract The micro-texture, grain size, morphology, size and distribution of the second phase in 6063 Al alloys significantly influence the comprehensive mechanical properties of alloys. By adding Sr to the 6063 Al alloys, this study performed a comparison of the effect exerted by micro-texture and grain refinement and explored the existence of Sr and its influence on the second phase. Inaddition, the influence mechanism for mechanical properties of the Sr-added alloys was also investigated. The results show that the phase structure of 6063 Al alloys is changed after adding Sr The Al 2 Si 2 Sr intermetallic compound is formed, and numerous substructures are developed during dynamic recovery and recrystallization. Moreover, after adding Sr element, the grain size of 6063 Al alloys is reduced from 33.45 μ m to 24.04 μ m. Small-angle grain boundaries increase, while large-angle grain boundaries decrease. Sr element changes the micro-texture of 6063 Al alloys significantly when Cube{100}〈001〉, Goss{110}〈001〉 and S {123}〈634〉 become Cube{100}〈001〉. The tensile strength, yield strength and Brinell hardness of 6063 Al alloys increase by 59.67%, 69.36% and 36.63%, respectively. Taken together, the Sr element strengthens the mechanical properties of 6063 Al alloys through fine-grained strengthening.