Preparation of aluminum foams and their sandwiches by accumulative roll-bonding

Aluminum foams were prepared by accumulative roll-bonding (ARB). Their porosity and pore mor- phology were studied by weighing and optical microscopy, respectively. It is found that aluminum foams prepared by ARB with TiH₂ powder as the blister have optimum performance within the foaming temperature of 660 to 680 ℃ and the foaming time of 6 to 10 min. The optimum values of foaming temperature and foaming time are relevant to blister content. With 1.5% TiH₂ at 670 ℃ for 8 min, the porosity and pore size of aluminum foams can reach 42% and 0.43 mm, respectively. Taking the aluminum foam by accumulative roll-bonding as the core, TC4 titanium alloy/aluminum foam and 1Crl8Ni9Ti stainless steel/aluminum foam sandwiches were produced by roll cladding. The interface morphology of these sandwiches was investigated by optical microscopy and energy spectrum analysis. A conversion zone forms by combination reaction between the face plate and the core plate, leading to metallurgical bonding at the interface.