Microstructure and age hardening behavior of Al/Fe bimetal prepared by one-step compound casting

Al-7Si-0.6Mg/Fe bimetal was prepared by compound casting; it was heat-treated to investigate the age hardening behavior of the aluminum matrix near the interface. Metallurgical bonding of the interface is accompanied by the formation of an oxide layer in the aluminum matrix near the interface. The inter metallic layer grows at the expense of the Si and Mg2Si particles within the diffusion reach during the solution heat treatment. The fraction of both AlFeSi and Si is low near the interface, the fraction of the AlFeSi phase is the highest just outside the oxide layer and decreases with increasing distance from the interface, which is accompanied by the increase in the fraction of the Si phase. The presence of the continuous oxide layer decreases the age-hardening ability and bonding strength of the aluminum matrix near the bimetal interface; such a negative effect is mitigated by the broken oxide layer. The lower age-hardening ability is resulted from the segregation of the Mg element to the oxide layer. (c) 2022 Elsevier B.V. All rights reserved.