Preparation of spray deposited aluminum alloy sheets via novel rolling technique

A novel ceramic rolling technique was developed to improve the formability of spray deposited porous aluminum alloy sheets,in which the sheet preform was canned and ceramic particulates were adopted as the medium for transferring pressure to make a homogenous hydrostatic stress field. The fractional thickness deformation,fractional longitudinal elongation,and fractional lateral spreading were calculated from the dimensions of samples before and after ceramic rolling. The results show that the flowing of metals in the longitudinal and transverse directions can be restrained during rolling. So ceramic rolling can effectively improve the density of the spray deposited performs. When the thickness reduction ratio is up to about 60%,the full density preforms can be obtained. The effect of the kinds of ceramic particulates,including Al2O3,SiO2 and graphite on the densification behavior of the preforms during rolling was investigated. The results imply that the Al2O3 particles with the size of about 74 μm are most effective.