Properties of the thermally stable Al95Cr3.1Fe1.1Ti0.8 alloy prepared by cold-compression at ultra-high pressure and by hot-extrusion

An Al95Cr3.1Fe1.1Ti0.8 (in at.%) alloy was made into rapidly solidified powder by melt atomization. The powder was compacted by two processes: 1) uni-axial cold compression at an ultra-high pressure of 6 GPa and 2) hot extrusion at 480 °C. The structures, mechanical properties and thermal stability of both materials were compared with the commercial AlSi12Cu1Mg1Ni1 (in wt.%) casting alloy, which is generally considered to be thermally stable. It was found that cold compression at ultra-high pressure created a compact and porosity-free material, which was similar to the material that was prepared with the commonly used hot extrusion method. The Vickers hardness, compressive strength and compressive yield strength of the cold-compressed alloy were 161 HV, 680 MPa and 547 MPa, respectively, which were higher than the values obtained for the hot-extruded and casting alloys. The thermal stability of the hot-extruded Al95Cr3.1Fe1.1Ti0.8 alloy was excellent because its mechanical properties did not change significantly, even after 100 h of annealing at 500 °C. The mechanical properties and thermal stability of the investigated materials were discussed in relation to their structures and diffusivities of the alloying elements.