Thermal compression behavior and microstructural evolution of selective laser melted AlMgScZr high-strength aluminum alloys
摘要
The AlMgScZr high-strength aluminum alloy fabricated by selective laser melting (SLM) technology exhibits a “bimodal microstructure”, resulting in significant non-uniform deformation during thermal deformation. This study investigates the flow behavior of SLM-processed AlMgScZr aluminum alloy utilizing the Gleeble-1500D thermal simulation machine. The true stress–strain curves were amended based on the friction theory. Through determining the Zener-Hollomon parameters, the correlation between flow stress, deformation temperature, and strain rate during the high-temperature thermoplastic deformation of SLM-processed AlMgScZr aluminum alloy with a “bimodal microstructure” was established. In addition, the microstructural evolution during thermal deformation was analyzed. The results indicated that the predicted flow stress values obtained from the Arrhenius constitutive equation with coupled correction of thermal deformation parameters closely matched the experimental values. The correlation coefficient and the average absolute relative error of the corrected model were 0.999 and 2.766%, respectively, accurately predicting the thermoplastic deformation behavior of SLM-processed high-strength aluminum alloy with a “bimodal microstructure”. Furthermore, hot processing maps at different strains were established, identifying stable and unstable regions under different deformation conditions. Microstructural observations revealed different thermal deformation mechanisms under various deformation temperatures. Specifically, dynamic recrystallization characteristics dominated the microstructure at lower temperatures (300–360 °C), while dynamic recovery was dominant at higher temperatures (390–500 °C).