The influence of ECAP on the small punch creep of Al-4 vol.% Al4C3 composite

The creep behaviour of a composite based on an aluminium matrix reinforced by 4 vol.% Al4C3 was studied at temperatures of 623 and 723 K by small punch testing with a constant force. The composite was tested in two different states: (i) as received by mechanical alloying with hot extrusion (HE) as the final operation and (ii) with equal channel angular pressing (ECAP) superimposed on the hot-extruded material. The ECAP does not improve the observed creep resistance. The reduction of force leading to the same deflection rate is not very significant. This points out that the ECAP process of the present composite, which produces substantial strengthening at lower temperatures, is not accompanied by pronounced weakening of creep resistance at elevated temperatures. The threshold force in the ECAP material is about 5 N weaker than in the HE material.