Infl uence of Heat Treatment on Precipitation Behavior and Mechanical Properties of Extruded AZ80 Magnesium Alloy

By means of annular channel angular extrusion technology and solution treatment,the AZ80 supersaturated solid solu-tion was prepared.Theβ-Mg 17 Al 12 precipitate morphologies analysis along with its sizes and area fraction measurement was performed to investigate mechanical properties variation of alloy at various aging temperature.The results indicated that after solution treatment,the intergranular precipitate of as-extruded alloy was re-dissolved into the matrix,eff ectively decreasing the stress concentration,which was benefi cial to the enhancement of elongation.At aging temperatures of 300°C,Widmanstatten structure,lath-shaped precipitate,and intergranular precipitate were observed,while at 175–200°C,cellular structure and oval-shaped particle were also identifi ed.The morphology,area fraction,size of the precipitates,and PFZs(precipitate free zones)width worked together to aff ect the age-hardening behavior of the alloy.The strength and hardness of the peak-aged samples decreased with the increase in aging temperature,which is primarily attributed to the reduction in cellular structure area fraction and the corresponding increase in the interlamellar spacing,and the coarsening of the rhombus precipitate.