Age-hardening behavior of Al-Mg-Si alloys using steam

Steam aging behavior of Al-Mg-Si alloys was investigated in order to clarify if steam could enable to induce precipitation. Age-hardening behavior was evaluated by Micro-Vickers hardness tests and differential scanning calorimetry (DSC). As a result of steam aging, that is an aging heat treatment utilizing thermal energy of steam, it was revealed that age hardening occurs in Al-Mg-Si alloys even in a steam atmosphere. When steam aging at 100°C was subjected to the alloys, the age hardening was suppressed compared to that of the alloys subjected to pre-aging at the same temperature, although the age hardening was superior to the alloys subjected to natural aging. On the other hand, it was clarified that superior age hardening was exhibited by subjecting to steam aging immediately after pre-aging at 100°C for 1.8 ks. Therefore, it was possible to induce age hardening by the thermal energy of steam, furthermore, an excellent age hardening could be raised via steam aging by appropriate thermal history based on the formation behavior of nanoclusters. © 2018 The Japan Institute of Light Metals.