The mechanical behavior of a nanostructured 5083 Al–Al 85Ni 10La 5 composite that was processed via consolidation of cryomilled 5083 Al and amorphous Al 85Ni 10La 5 powder was investigated in the temperature range of 25–400 °C. The devitrified Al 85Ni 10La 5 phase revealed high thermal stability against growth during the consolidation process and resulted in a grain size of approximately 200 nm. The 5083 Al–Al 85Ni 10La 5 composite exhibited superior elevated temperature properties when compared to that of nanostructured or coarse-grained 5083 Al alloy. The mechanical behavior of the 5083 Al–Al 85Ni 10La 5 composite was analyzed in the context of the deformation mechanisms that are active in the 5083 nanostructured matrix.