Influence of deformation at elevated temperatures on stability of microstructure and mechanical properties of UFG aluminum alloy

Ultrafine-grained (UFG) state with a mean grain size of 180 nm was produced in a 6060 alloy of the Al-Mg-Si system by high pressure torsion (HPT). The UFG Al 6060 alloy demonstrated high strength: microhardness of 120 Hv and ultimate tensile stress of 525 MPa at room temperature. The tensile tests were carried out at temperatures 120, 150 and 180 degrees C with the strain rate 10-2, 5 x 10- 3, 10- 3, 5 x 10-4 and 10-4 s- 1 to determine the best conditions for the manifestation ductility and study of changes in strength of the study material. It established, that the UFG alloy retains an increased 80% of level of strength at room temperature after deformation at elevated temperatures in the temperature range 120-150 degrees C. The results obtained are compared with changes of the microstructure and strength of the UFG alloy after annealing under similar temperature-time conditions.

Automated summary

Ultrafine-grained state with a mean grain size of 180 nm was achieved in a 6060 alloy through high pressure torsion (HPT), resulting in high strength properties such as a microhardness of 120 Hv and ultimate tensile stress of 525 MPa at room temperature. The alloy also showed a significant retention of strength after deformation at elevated temperatures, demonstrating its potential for high temperature applications.