Simulation And Experimental Study On Interface Bonding Behavior Of 2024/6061bimetallic Aluminum Alloy Subjected To Casting And Rolling

Bimetallic composites are often used in the fabrication of key components of machinery in deep space and deep-sea exploration.They can combine the excellent properties of two single metal materials and meet the service requirements in extremely harsh environments,such as high temperature,high pressure,and strong corrosion.2024/6061 bimetallic aluminum alloy is a lightweight composite material,and in-depth research on its interface bonding behavior can lay a foundation for its application in lightweight components.In this paper,the high temperature flow behavior of 2024/6061 bimetallic aluminum alloy was studied by hot compression experiment,and the interface evolution was observed.The hot rolling bonding process of 2024/6061 bimetallic casting blank was simulated by Abaqus finite element software,and the optimal hot rolling process was determined.Then,using the rolling experiment to research the influence of the interface structure evolution and bonding properties of the casting blank on different pouring interval,different rolling temperature and different pressure.The results show that:（1）The flow stress of 2024/6061 bimetallic aluminum alloy decreases with increasing of temperature and decreasing of strain rate,its flow behavior of high temperature is the result of strain hardening and dynamic softening working together.The Arrhenius constitutive model considering strain compensation is constructed,by analyzing the true stress-strain curve.（2）2024/6061 bimetallic aluminum alloy grain size equation is established.The equation show that the recrystallization is easy to occur at high temperature and low strain rate,and the recrystallization degree increased with the increase of strain.In addition,the strain rate decrease making the diffusion of interfacial elements is accelerated.Interfacial bonding mechanism is metallurgical bonding.（3）With the increase of deformation amount,the deformation temperature increases,and the strain rate decreases,and the equivalent strain develops from 6061Al and 2024Al to the bonding interface,which improves the uniformity of the distribution of equivalent strain and temperature.The optimum process parameters obtained by simulation are rolling temperature is 450℃,strain rate is 0.5 s^-1 and deformation amount is 75%.（4）The experimental results of 2024/6061 bimetallic aluminum alloy rolling with different pouring intervals show that the metallurgical bonding effect of bimetallic with 15 s interval is the best.Cast blanks bonding interface width is 90μm,and the elements Cu,Mg and Si on both sides of the interface have different degrees of interdiffusion.After rolling,the width of the interface was increased to 280μm.The grain at the bonding interface was refined,and the diffusion degree of Cu element increased greatly,the diffusion distance of Cu element increased from 50μm to 240μm.（5）After further study of the sample with intervals of 15s,it is shown that the rolled sample has better property at 450℃and 75%deformation amount with solution aging.The tensile strength of 257 MPa,the yield strength of 198 MPa and elongation of 15.8%,and the tensile fracture morphology is characterized by ductile-brittle mixed fracture.