The Preparation And Interface Behaviors Of Cu/Al/Cu Composite Foil

With the ever-increasing world energy crisis, reducing energy consumption has become the first problem that industrial countries care. As a new composite material, aluminum composite material has excellent overall performance, which is widely used in electronics, electrical, electronic, mechanical, energy and other industries.In this paper, copper-aluminum composite foils with different alloy compositions were prepared by cold rolling and warm rolling, and the influences of rolling types and alloy elements on bimetallic coordination deformation and interface were also studied. In addition, at different annealing conditions, the microstructure of interface, nucleation and growth of intermediate phase, diffusion of elements of alloy were analysed, which provided theoretical and practical technical reference for preparing good Cu-Al composite foils.Through hardness testing, metallographic microstructure analysis, scanning electron microscopy (SEM) analysis and XRD analysis detection means, Cu-Al composite foil morphology and interface behavior were researched, and the following conclusions were obtained:1. In order to get straight interface of Cu-Al composite plate, the coordinate deformation of thermometal must be ensured. The coordinate deformation mainly depends on the similar plastic deformation and strength. The glancing flatness of interface of Cu-Al composite plate is still bad if the thermometal has similar plastic deformation but very large intensity difference. The glancing flatness of interface of Cu-Al composite plate can be realized if the thermometal has large plastic deformation difference but small strength difference. Thus it can be seen that the key point of straight interface for Cu-Al composite plate is whether the two components have similar strength. The relative difference of hardness of Cu layer and Al layer plays a key role.2. The Cu-Al composite plate with straight interface is essential for producing Cu-Al composite foil. The Cu-Al composite plate with curve interface can not have coordinate deformation in the subsequent deformation process, and the Cu layer will break. The Cu-Al composite plate with straight interface can have coordinate deformation in the subsequent rolling process, and will guarantee good quality product.3. As heat treatment increases the activity of metal atoms, so under the condition of rather smaller deformation, good combination of copper and aluminum bond can be achieved, At the same time, due to the smaller deformation, it is easier to obtain flat Cu-Al interface, while laying a further foundation to obtain a good Cu-Al composite foil.4Temperature and time of annealing have strong influence on intermediate phase, when annealing temperature is200℃, the interface is mainly aluminum based solid solution and copper base solid solution. When annealing temperature is300℃, the interface present double structure metal compounds after0.5hour. When annealing temperature is400℃for1hour, the interface is composed of obvious three layer structure(Cu9Al4, CuAl, CuAl2).5. Annealing at low temperature for long time, the growth process of Cu-Al intermediate phase are as follows:the incubation periodâ†'the nucleation of new phase (Cu9Al4) in island at interface local area, lateral growthâ†'the nucleation of second phase(CuAl2) and third phase is respectively in the first phase(Cu9Al4) and between the first phase(Cu9Al4) and the second phase(CuAl2),and synchronous lateral growth of three-phaseâ†'horizontal continuous growth into piecesâ†'the longitudinal overall growth.6. Micro alloy elements in the middle phase has certain effect, at300℃, when annealing time is from0.5to1hour, Si element has no inhibit effect on the growth of intermediate phase, when annealing time is more than1hour,. Si element inhibit s the growth of intermediate phase; When annealing temperature is400℃, with the increase of annealing time, the inhibition of Si on intermediate phase increased. Annealing at low temperature for long time or at high temperature, the more Si content, the higher the stronger the inhibition.