Evolution of mechanical properties and its mechanisms of pre-twinned pure magnesium and AZ80 magnesium alloy during annealing

doi:10.13251/j.issn.0254-6051.2022.05.010

Abstract

Abstract: Extruded pure magnesium and AZ80 magnesium alloy prepared by the same process were pre-compressed by 6% respectively, then the specimens with and without pre-compressing were annealed at 180 ℃ for 20 h. The microstructure and mechanical properties were characterized by using optical microscope, scanning electron microscope, transmission electron microscope and compressive test machin, by which the evolution of mechanical properties during annealing and its mechanisms were investigated for the pre-twinned pure magnesium and AZ80 alloy. The results show that the yield strength of the 6% pre-compressed pure magnesium annealed at 180 ℃ for 20 h is lower than that of the unannealed, which indicates that no annealing hardening occurs in the pure magnesium. The yield strength of the AZ80 alloy without pre-compressing annealed at 180 ℃ for 20 h is nearly equal to that of the AZ80 alloy before annealing. However, the yield strength of the 6% pre-compressed AZ80 alloy annealed at 180 ℃ for 20 h is 20 MPa higher than that before annealing, which is resulted from a great deal of white second-phase particles precipitated in the twins and at the twin boundary that prevent dislocation gliding and twin expanding. Thus, the 6% pre-compressed AZ80 alloy has obvious annealing strengthening effect.

Key words: pure magnesium, AZ80 magnesium alloy, annealing strengthening, second-phase particles

CLC Number:

TG146.2

He Jiejun, Wu Lushu. Evolution of mechanical properties and its mechanisms of pre-twinned pure magnesium and AZ80 magnesium alloy during annealing[J]. Heat Treatment of Metals, 2022, 47(5): 65-70.

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