Mechanically milled pure aluminium particles were consolidated into bulk material using back pressure equal channel angular pressing (BP-ECAP) at 373 K. Compressive yield strengths of 380 and 422 MPa with ultimate strengths over 500 MPa were obtained after 4 and 8 passes of ECAP, respectively. Further strengthening was observed after heating at 673 and 773 K. The age hardening and thermal stability were attributable to the formation of Al4C3 particles from a solid-state reaction during the isothermal heat treatments.