Plastic instability criterion based on new necking parameters for Cu–Al, Cu–A5052, and Cu–A5083 roll-bonded laminated metal composites fabricated without post-annealing.

Although laminated metal composites fabricated by accumulative roll bonding (ARB) undergo kink-band formation, there are no guidelines for optimizing their fabrication to avoid necking and shear localization without post-annealing. The necking of the composite layers during rolling generates non-uniformities that may degrade the mechanical performance of the composite. This paper proposes a model for laminated metal composites that aims to quantitatively assess and predict necking based on the work-hardening of each layer. Cu–Al-, Cu–A5052-, and Cu–A5083-laminated metal composites were fabricated using ARB at room temperature (~300 K) without post-annealing, and they were subjected to mechanical and microstructural analyses. A normalized neck amplitude was introduced as a new parameter that accurately predicted the degree of necking observed experimentally. Another new parameter, an instability index , was introduced to frame the necking criterion of the hard layers. A plastic instability criterion framed based on the new parameters accurately predicted the degree of necking in the hard layers of the as-prepared laminated metal composites. These findings may be applied to guide the fabrication of metal composites of any composition using the ARB process. [Display omitted] • Laminated metal composites (LMCs) were fabricated using ARB without post-annealing. • Normalized neck amplitude can assess the experimentally observed degree of necking. • Instability index predicts the necking of the hard layers in the LMCs. • These two parameters aid in framing plastic instability criterion for LMCs. • The findings are instrumental in fabricating stable LMCs using ARB. [ABSTRACT FROM AUTHOR]