Microstructure, strength and creep of aluminium-nickel open cell foam

Al–6.4 wt% Ni open-cell foams produced by replication are tested in compression and in tension at room temperature and creep tested in tension at 450°C. The mechanical behaviour of this foam at room temperature is consistent with that observed for other open-cell metallic foams. A strong dependence on relative density as well as dependence on stress and temperature of the steady-state creep rate are captured by the model described by Mueller et al. [Scripta Mater. 57 (2007) p.33], itself a simplification of variational estimates by Ponte Castañeda and Suquet [Adv. Appl. Mech. 34 (1998) p.171]. The foam exhibits two regimes of creep, separated by a critical stress; these features can be interpreted on the basis of the microstructure of the Al–6.4 wt% Ni alloy making the foam. This microcellular eutectic Al–Ni exhibits attractive creep failure resistance compared to other open-cell aluminium alloy foams.

Keywords

• aluminium alloy,
• cellular metals,
• plastic deformation,
• creep