Effect of pre-deformation on precipitation behavior of AZ80 alloy: Comparison of slip- and twinning-dominant deformation

초록

This study investigates the effect of the deformation mode on the precipitation behavior of an extruded Mg-8.0Al-0.5Zn-0.2Mn (AZ80) alloy. The alloy samples are compared after the application of 3.5% tension and 3.5% compression along the extrusion direction to induce slip-dominant and twinning-dominant deformation modes, respectively. The pre-compressed (PC) sample, which contained numerous {10-12} tension twins, has a reduced grain size and a higher internal strain than the pre-tensioned (PT) sample, which is attributed to the inherent internal strain that occurs during the formation and growth of the twins. As a result, the precipitation behavior of the PC sample is accelerated, leading to its short peak aging time of 32 h, which is lower than those of the PT and as-extruded samples (48 and 100 h, respectively). Furthermore, fine continuous precipitates (CPs) rapidly form within the {10-12} twins, contributing to the enhanced hardness. Discontinuous precipitates (DPs), which have a hardness comparable to the CP-containing twinned regions, in the PC sample experience less coarsening during aging than those in the PT sample due to growth inhibition by the {10-12} twins. Ultimately, the {10-12} twins generated under the twinning-dominant deformation condition lead to enhanced precipitation behaviors, including the preferential formation and refinement of CPs and the suppressed coarsening of DPs. Consequently, pre-deformation that occurs {10-12} twinning exhibits more pronounced effects on precipitation acceleration and microstructural modification than slip-inducing pre-deformation. (c) 2024 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer review under responsibility of Chongqing University

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