Hot Deformation Behaviour of Cu/Al Laminated Composites under Interface Constraint Effect

Abstract

Abstract:In order to understand the hot deformation behavior of novel Cu/Al laminated composites, isothermal hot compression tests were conducted by Gleeble-1500D thermo-mechanical simulator. And the effect of bonding interface, deformation temperature and strain rate on the deformation behavior was analyzed. Results show that under the interface constraint effect, soft Al layer trends to flow synchronously with hard Cu layer. And further microstructure examinations indicate the cooperative deformation capability of Cu/Al composites increases with increasing stain rate and decreasing deformation temperature. Strain hardening exponent, calculated based on the true stress-true strain data, also proves the effect of deformation temperature and strain rate on the cooperative deformation behavior. Meanwhile, unique composites structure allows the Al matrix to exhibit the characteristic of dynamic recrystallization during the hot deformation process. Lastly, strain compensated Arrhenius-type constitutive equation was employed to describe the coupling effect of temperature, strain rate and strain on the flow stress. Key words: Cu/Al laminated composites; deformation behavior; interface; microstructure; constitutive equation IntroductionWith the rapid development of modern industry, light-weight is an intense pursuit goal for more economical and green development at the basis of keeping original mechanical properties. Copper/aluminum (Cu/Al) laminated composites have been developed to meet these demands and several fabricate methods also have been presented in recent years [1][2][3][4][5]. Practices indicate that compared to monometallic copper or copper alloy, Cu/Al composites can reduce the weight of 40 ~ 50 %, save the cost of 30 ~ 50 % and keep almost consistent electrical and thermal conductivity [6]. Therefore, Cu/Al laminated composites have been utilized in a number of areas such as power, communication, architecture and aerospace [5,7]. Until now, numerous studies about Cu/Al composites are mainly focused on the fabricate technologies [1][2][3][4][5], thermal treatment crafts [8][9][10] and bonding mechanisms [11,12]. However, thermal mechanical machining such as hot rolling and tension also are necessary for Cu/Al composites in order to meet various industrial needs, to the authors' knowledge, related research is not available.For the hot deformation behavior of metal materials, the essence is dynamic competition between work hardening and dynamic softening (including dynamic recrystallization and dynamic recovery), and the process is significantly affected by deformation temperature, strain rate, microstructure and so on [13]. Until now, Arrhenius-type constitutive equation is a kind of commonly used mathematical model to describe the relationship between the flow stress and deformation temperature, strain rate and deformation activation energy during the hot deformation process [14]. And the hot deformation behaviors of constituent metals of Cu/Al laminated composites have been investigated respectively thro...