2009 Volume 50 Issue 4 Pages 879-884
The surface region of electric-discharge-machined aluminum foams was modified by the friction-surface-modifying and rolling (FSMR) process. A new surface was successfully obtained through the FSRM process, which was considerably smoother and denser than that of the unprocessed aluminum foam. In the FSMR process, the amount and morphology of the residual pores are mainly dominated in the surface of metallic foams by the friction surface modification (FSM) process stage. The smoothest surface, however, was formed for the friction-surface-modified (FSMRed) aluminum foam, which was attributed to the additional rolling process after the FSM process. This result demonstrates that the FSMR process is a very effective technology in controlling the surface morphology of the metallic foams through the cell structure control of the surface region. For the FSMRed aluminum foam, the highest average bonding strength, yield strength and toughness were obtained, which were nearly equivalent to 1.4, 2 and 1.6 times the values of the unprocessed aluminum foam, respectively. This result shows that, in the FSMR process, the additional rolling process after the FSM process is very effective in enhancing the bonding characteristics of the metallic foams by smoothening the surface. In addition, the above-mentioned bonding characteristics were remarkably increased with the decrease in the surface roughness, suggesting the surface morphology is a very important parameter in controlling the bonding characteristics of the metallic foams. The experimental results revealed that the FSRM process is a very effective technology for the improvement of the bonding characteristics of the metallic foams through the control in the surface morphology.
