Synthesis and Industrial Trial of Non-Equilibrium Aluminum Alloys with a Combination of High Heat-Resistance, High Strength and Good Workability

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In order to develop novel elevated-temperature Aluminum alloys having a combination of high ambient-temperature strength of 600 Mpa, high elevated-temperature strength of 300 Mpa at 573 K, high heat resistance for 100 hr at 723 K, high workability and high wear resistance, we synthesized and investigated the mechanical properties of many Al-Ti-Cr-X rapidly solidified powder metallurgy alloys and their composites. Accordingly, we have succeeded in synthesizing Al_<92.5>Ti_<2.5>Fe_<2.5>Cr_<2.5> RS P/M alloy that reached our target of this study. The RS P/M alloy exhibited the following mechanical properties.(1) The alloy exhibited high tensile strength at ambient temperature. The tensile strength was ranging from 600 MPa to 660 MPa and the elongation was 3-4 %.(2) The alloy exhibited high tensile strength at elevated temperature. The tensile strength was 480 MPa, 320 MPa and 150 MPa at 473K, 573K and 673K, respectively.(3) The alloy exhibited high thermal stability. The decrease in ambient-temperature strength due to annealing at 723K for 100 hr and 623K for 1000 hr was within 10 %.(4) The alloy can be hot-worked at high strain-rate with keeping the high ambient-temperature strength of about 550 Mpa. The alloy exhibited a large elongation at high strain-rate of 10^<-1> to 1 s^<-1> at 823 K where the decease in ambient-temperature strength was within 15 % for 5 hr.(5) The composite with 2.5 vol% SiC particles exhibited improved the Young's modulus and the wear resistance at high temperature of 473 K.Some companies are trying tests of practical application of the Al_<92.5>Ti_<2.5>Fe_<2.5>Cr_<2.5> RS P/M alloy developed in this study.