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 450C. 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 Castaneda 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.