Influence of a low-frequency alternating magnetic field on hot tearing susceptibility of EV31 magnesium alloy

Abstract

The effect of a low-frequency alternating magnetic field (AMF, 0 A 0 Hz, 5 A 10 Hz, 10 A 10 Hz, 15 A 10 Hz) on the hot tearing susceptibility (HTS) of a magnesium alloy (EV31) was systematically studied using a combination of experiment and numerical simulation. By observing the macroscopic hot cracks in hot joints of the "T" samples, the hot tearing tendency of the samples was analyzed. The HTS of the alloy can be predicted via numerical simulation and the crack susceptibility coefficient (CSC). The microstructure and morphology of the hot tearing zone of EV31 were investigated using scanning electron microscopy (SEM). Results show that increasing the magnetic field strength reduces both the alloy solidification temperature range and the dendrite coherency temperature, which increases the feeding time during solidification and decreases the HTS of the alloy. When the magnetic field parameters are 10 Hz 15 A, the EV31 alloy shows the lowest HTS. The main component of the second phase in the microstructure is Mg12Nd. This study also found that the electromagnetic field can effectively refine the grains, purify the melt, and reduce the oxide content in the melt. The obtained simulation results are consistent with the experimental results.

Keywords

• ev31 magnesium alloy; electromagnetic field; hot tearing susceptibility; microstructure; dendrite coherency temperature