Metal foaming by powder metallurgy process: investigation of different parameters on the foaming efficiency

Abstract

Aluminium foams, produced by powder metallurgy process, have significant potential applications for uses in weight-sensitive structural parts. Problems in the production of metal foams arise from the lack of knowledge in the control of process parameters. The results are frequently uneven and un­predictable variations in the structure and properties of the final foamed parts are observed. This paper aims to investigate the effect of different para­meters of the powder metallurgy with foaming agents process on the foaming efficiency. The parameters examined included the powder morpho­logy, the compaction pressure and the foaming temperature. During the foaming stage, for each set of parameters the porosity-time (Pf-t) diagrams were created and the foaming efficiency was calculated (η=Pfmax). Results indicated that the highest foaming efficiency was observed at the specimens with the fine alu­min­ium powder, with high (700 MPa) compaction pressure and high foaming temperatures (800 oC). Finally, compression tests were per­formed on the foamed specimens with the higher foaming efficiency in order to investigate their s-e response. Furthermore, average compressive strength and density were estimated and presented.

Keywords

• Aluminium foam
• Foaming process
• Foaming efficiency
• Mechanical properties
• Porosity