Effect of a low-voltage pulsed magnetic field on the microstructure and mechanical properties of AZ80 alloy

摘要

Effect of a low-voltage pulsed magnetic field(LVPMF)on the solidified microstructure and mechanical properties of Mg-Al-Zn alloy was studied.When the LVPMF is applied during solidification,the as-cast microstructure is significantly refined and α-Mg is modified from developed dendrite to fine rosette.This morphology modification is caused by the accumulation of Joule heat on dendrite tip.Accumulation of Joule heat on dendrite tip melts the dendrite tip and increases the radius of curvature.The increased radius of curvature at the dendrite tip lowers the growth rate and results in the formation of rosette α-Mg.With the application of the LVPMF,β precipitates,formed in the interdendritic liquid region,are connected to each other due to the smaller dimension of the primary and secondary arms and larger volume fraction of the β precipitates between the dendrites.Experimental results indicate that the yield strength and ultimate tensile strength are both increased under with the application of the LVPMF.However,elongation is slightly decreased with the application of the LVPMF due to the continuous β precipitates.