Abstract
Powder metallurgy (P/M) alloys of AFCT (Al–6.3%Fe–3.8%Cr–3.3%Ti)–26P/M, AFCT–125P/M, ACFT (Al–5.5%Cr–4.1%Fe–3.3%Ti)–26P/M, ACFT–125P/M, AFCV (Al–6.3%Fe–3.6%Cr–3.6%V)–75P/M, AFMT (Al–6.0%Fe–3.8%Mn–3.2%Ti)–26P/M and AFMT–125P/M were prepared by extruding at 673 K gas atomized powders with sizes smaller than 26 μm, 75 μm and 125 μm, respectively. The constituent phases were Q.C. (quasicrystalline)+Al+Al23Ti9 +Al13Fe4 for the ACFT–P/M alloy, Q.C.+Al for the AFCV–75P/V, Q.C.+Al+Al23Ti9+Al13Fe4+Al6Mn for the AFMT–P/M alloy. The ultimate tensile strength (σUTS), 0.2% proof strength (σ0.2), plastic elongation (εP), Young's modulus (E) and Vickers hardness (HV) of the P/M alloys are in the range of 495 to 650 MPa, 370 to 550 MPa, 3.3 to 7.3%, 80 to 91 GPa and 150 to 192, respectively, at room temperature. The σUTS and σ0.2 of the AFCT–26P/M and ACFT–26P/M alloys were higher than 300 MPa even after heating for 100 h at 573 K. The quasicrystalline particles in the P/M alloys have an icosahedral structure and their particle size is 200 to 900 nm. In the ACFT–26P/M alloy with high elevated-temperature strength, the particle size and morphology of the icosahedral phase remained unchanged even after heat-treatment for 300 h at 573 K. The specific wear rate of the AFCT–26P/M alloy is as smaller as 2.7 × 10−7 mm2/kg at the sliding velocity of 0.5 m/s and 2.8 × 10−7 mm2/kg at 2.0 m/s and almost independent of sliding velocity.
