On tension/compression asymmetry of an extruded nanocrystalline Al-Fe-Cr-Ti alloy

A multi-phase nanocrystalline Al93Fe3Cr2Ti2 alloy containing 30 vol.% intermetallic particles was prepared via mechanical alloying, followed by hot extrusion. Tensile and compressive tests at ambient and elevated temperatures were performed on this nanocrystalline alloy. The alloy exhibited significant difference in deformation behavior between tension and compression at 25, 200 and 300 °C. However, the strengths obtained in tension and compression were similar at 400 °C. Systematic microstructure examinations and deformation mechanism analyses indicate that the asymmetry of this nc Al93Fe3Cr2Ti2 alloy is related to its dislocation mediated plastic deformation mechanism, its nanoscale grain microstructure, and premature brittle failure in tension tests.