Fabrication of Al/Ni multilayers with excellent layer continuity by combination of accumulative pack rolling and roll bonding

Abstract

Fabrication of Al/Ni multilayer sheets with great layer continuity has always been a challenge due to early necking and rupture of Ni layer in rolling process, which usually results in a structure with Ni fragments in Al matrix and induces poor thermal performance. This study investigates the fabrication and characterization of Al/Ni multilayer sheets with a focus on achieving excellent layer continuity. The multilayers were prepared using accumulative pack rolling (APR) and roll bonding techniques, combining aluminum alloys (AA1050 and AA7075) with Ni to form laminated composites with controlled thickness ratios. The mechanical compatibility between materials by heat treatment and warm roll bonding was emphasized to mitigate plastic instability, such as shear banding and necking, which disrupt layer continuity. Differential scanning calorimetry (DSC) was employed to evaluate the thermal performance and the formation of intermetallic compounds, including Al₃Ni and Al₃Ni₂. The results indicate that AA7075/Ni multilayers exhibit excellent structural integrity and thermal response compared to AA1050/Ni. While achieving bilayer thicknesses as thin as 5–10 μm, the study also highlights the issues of bonding quality in thinner layers and the impact of thickness ratios on heat release efficiency. This work demonstrates the potential of heat treatment and warm roll bonding as cost-effective, scalable methods for fabricating high-performance AA7075/Ni multilayers and provides valuable insights into optimizing their design for thermal and mechanical applications.