Formation of intermetallic compounds of Cu/Al multilayer foils during cold rolling

Abstract

Sci China Mater 2015, 58: 574-583 ening may prevent severe plastic deformation. Therefore, understanding whether chemical reactions can occur and new phases can be formed during producing multi-layered composites by severe plastic deformation is important. However, these behaviors are not well understood. Accordingly, the occurrence of chemical reactions in heavily strained dissimilar metals at room temperature must be demonstrated.We want to determine the behavior of a laminated-metal composite when pressure is applied. A four-high micro-foil mini mill (3M mill) was previously developed to roll extremely thin strips [29]. Using the 3M mill, a 0.13-mmthick Cu/Al composite foil was obtained at room temperature without annealing. Surprisingly, some new phases were observed at the interfaces of the roll-bonded Cu/Al composite foil. Transmission electron microscopy/selected area eltrecon diffraction (TEM/SAED) and scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM/EDS) reveal that the new phases are composed of Al 2 Cu/AlCu/Al 4 Cu 9 . Thus, room-temperature chemical reactions conclusively occur under force effects. EXPERIMENTAL SECTIONSpecial rolling process Pure copper T2 (99.8% purity) with size 100 mm×30 mm×0.21 mm (length×width×thickness), and pure aluminum A1100 (99.7% purity) with size 100 mm×30 mm×0.20 mm were selected as initial materials. To obtain good bonding between the metal layers, aluminum and copper sheets were annealed at 500°C and 600°C for 1 h, respectively, and were polished using a stainless steel brush to remove surface oxidation films. After ultrasonic washing in acetone and hot air drying, 23 layers were alternately stacked (11 layers Al and 12 layers Cu). The sample was cold rolled at room temperature using six passes. The first two passes were performed on a two-high mill with a roll diameterIn metallurgical theory, the generation of new phases requires high temperature diffusion over a long period of time. Here, we report an experimental study of the generation of new phases using large mechanical deformations and high pressure, rather than heat. A 4.83-mm-thick 23-layered Cu/Al sandwich strip was formed by cold rolling. When the Cu/Al sandwich was further rolled to a 0.13-mm-thick foil on a four-high micro-foil mini mill at room temperature, some rectangular-shaped phases appeared at the Cu/Al interfaces. The scanning electron microscopy, transmission electron microscopy, and X-ray diffraction analyses reveal that the phases are a mixture of Al2Cu/ AlCu/Al4Cu9, which indicates that chemical reactions occur at the Cu/Al interfaces during cold deformation. This study provides new insights into the design and development of composite materials for various applications.

Synthetically Tuned Atomic Ordering in PdCu Nanoparticles with Enhanced Catalytic Activity toward Solvent-Free Benzylamine Oxidation

“…The synthesis of IM phases typically requires high temperature; therefore, the design of IM nanoparticle (NP) catalysis with high surface areas is proven to be challenging. During the past few years the development of low-temperature solution-chemistry strategies for synthesizing IMNPs includes various methods such as coreduction, colloidal, hydrothermal synthesis, etc. ,, The formation of IMCs depends upon the mixing mode of each constituent element, its chemical composition, redox potential, structural properties, and the morphology of the particles . IMCs have potential in the field of catalysis, as they provide an ideal opportunity to study the correlation between the atomic ordering and the catalytic activity .…”

Investigation of Formation Behaviour of Al–Cu Intermetallic Compounds in Al–50vol%Cu Composites Prepared by Spark Plasma Sintering under High Pressure

“…Yu et al reported the formation of interfacial Al–Cu ICs via cold rolling [ 18 ]. According to their report, the dislocations accumulated near the interfaces owing to compaction pressure weakened the inter-atomic bonding forces between the individual Al (or Cu), leading to their higher diffusivity [ 27 , 28 ].…”

“…Generally, ICs are formed via thermal diffusion when heat is applied. A recent study revealed that ICs were partially formed at the interface between Al and Cu foils owing to the non-uniform accumulation degree of dislocations achieved via cold rolling (uniaxial high pressing) [ 18 , 19 ]. As the partial formation of ICs can enable direct contact between the metals at the interface, this approach was considered suitable for preventing the deterioration in thermal conductivity with an increase in the Al/Cu interface area.…”