Anisotropy and strain localization in steel foam

Steel foam fabricated by a powder metallurgical process was tested in uniaxial compression. The closed-cell foam samples exhibited anisotropy in compression, a phenomenon that was caused primarily by the ellipsoidal cell shapes within the foam. Yield strengths were 3 x higher in the transverse direction than in the longitudinal direction. Yield strength also showed a power-law dependence on relative density (n congruent to1.8). Compressive strain was highly localized and occurred in discrete bands that extended transverse to the loading direction. The deformation hands were comprised of collapsed cells, and deformation occurred in a sequential manner with repeating cycles of yield, collapse and densification of cells. Foam densification commenced when all of the foam was converted into deformation bands. (C) 2001 Elsevier Science B.V. All rights reserved.