Strengthening of compound casting Al/Mg bimetallic interface with Ni interlayer by vibration assisted treatment

Abstract

To improve the microstructure of compound casting Al/Mg bimetallic interface and optimize the bonding performance, the vibration assisted treatment and the Ni interlayer coating treatment were combined. After the composite treatment, the thickness of the Al/Mg bimetallic interface decreased significantly, only 8.13% of the original interface thickness. The original large amount of brittle and hard Al–Mg intermetallic compounds (IMCs) no longer existed, and were replaced by the (Mg–Ni) layer dominated by Mg3Ni2Al, the Al3Ni layer and the Ni solid solution layer. The shear crushing effect and the convective stirring effect of the vibration assisted treatment provided more stable and good metallurgical bonding for the Al/Mg bimetallic interface after introducing Ni interlayer. On this basis, combined with the second phase strengthening effect of the newly precipitating Mg3Ni2Al, the bonding strength of the Al/Mg bimetallic interface significantly improved, from 35.47 MPa to 56.12 MPa, with an increase of 58.22%.