2023 Volume 64 Issue 2 Pages 429-435
This study aimed to improve the strength and ductility of Al–Mg–Si alloys by combining severe plastic deformation and heat treatment. A 6061 aluminum alloy subjected to equal-channel angular pressing (ECAP) after solution treatment was heated from 100°C to 400°C for 10 s. Results of electron backscatter diffraction analysis indicated that the fine grains obtained via ECAP processing in the present experiment remained after a short heating duration of 10 s at 400°C. Results from the hardness test suggest that the alloy starts to recover after a short-time heating at approximately 200°C, and that its strengthening phase precipitates at approximately 250°C. In the case of artificial aging without short-time heating after ECAP processing decreased the strength of the alloy, possibly owing to the effect of recovery (reduction in dislocation density) during the artificial aging. The 0.2% proof stress and ultimate tensile strength of specimens short-time heated at 200°C after ECAP processing increased by 18 and 15 MPa, respectively, owing to the subsequent artificial aging. We assumed that hardening due to precipitation strengthening was caused by the artificial aging, whereas the reduction in dislocation density was due to the short-time heating. Specimens short-time heated at 300°C after ECAP showed a significant decrease in strength after artificial aging. Although recovery occurred after ECAP processing followed by short-time heating, the precipitation state that occurred simultaneously contributed to the strength and ductility of the alloy in the subsequent artificial aging.
