Low temperature superplastic gas pressure forming of electrodeposited Ni/SiC_pnanocomposites

The superplastic deformation behavior of a Ni/SiCpnanocomposite was investigated under equibiaxial tension at a strain rate of 8.3 × 10-4s-1and various forming temperatures and die apertures. The average as-deposited nickel grain size was 40 nm, and the average SiC particle size was 50 nm. The experimental relative bulging height (RBH) values were measured, and compared with that predicted by a finite element method (FEM) model. It was found that the composite had exhibited good superplasticity, illustrating high RBH values, and the die diameter affected significantly its deformation behavior. The cavitation behavior of the composite was also examined, and found to be dependent on stress state and the total effective strain. As compared to the analytical results, the FEM predictions were shown to be in better agreement with the experimental thickness distribution, although a large discrepancy was observed for dies with small diameters.