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

• Published in: Journal of materials processing technology Vol. 306; p. 117634
• Main Authors: Miyajima, Yoji, Yamada, Takuya, Fujii, Toshiyuki
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.2022; Elsevier BV
• Subjects: Accumulative roll bonding; Aluminum; Annealing; Composite materials; Copper; Laminated metal composites; Laminates; Mechanical properties; Mille-feuille structure; Necking; Parameters; Plastic instability; Roll bonding; Room temperature; Shear localization; Stability criteria; Ultrafine grains; Ultrafine grains; Mille-feuille structure; Laminated metal composites; Accumulative roll bonding; Necking
• ISSN: 0924-0136; 1873-4774
• DOI: 10.1016/j.jmatprotec.2022.117634

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.