Characterization of Cr-Mo alloyed steel foams produced by evaporative and leachable space holder technique

Abstract

Steel foams have attracted a lot of attention in both academia and industry with unique properties such as low density, high strength-to-weight ratio, operating temperature, good energy absorption, electrical conductivity, and large specific surface. The development of production methods will increase the use of steel foam. In this paper, Cr-Mo alloyed steel foams having porosities in the range of 46.8-71.3% were produced by evaporative and leachable space holder techniques in powder metallurgy. The effect on the properties of removing the carbamide used as a space holder material from the porous structure by different methods was compared. Microstructural evaluations of the pore walls, pore size, pore walls thickness, and the compressive deformation behavior of steel foam were evaluated. Steel foams produced by both routes have a rather similar macropore structure but differences in pore wall structure such as micropore ratio and pore wall thickness. The differences increase with increasing porosity content. The mechanical properties are higher in foams produced by the evaporative route as compared to the leachable route at similar porosity due to its stronger cell wall.