| Aluminum alloy has been widely applied to electric power industry, transportation industry and aerospace industry because of its excellent properties, such as low density, high strength, good toughness, corrosion resistance, and so on. With the development of technology, the properties of traditional aluminum alloy can not satisfy the demand of industry. Due to its excellent mechanical properties at room and high temperature, good electrical conductivity and thermal conductivity, oxide dispersion strengthened(ODS) aluminum alloy has received general attention. In this study, ODS aluminum alloy was fabricated using ball milling, cold isostatic pressing, sintering, hot extrusion and cold drawing. Results showed that ODS aluminum prepared by powder metallurgy exhibites excellent properties, and the fabrication method is suitable for industrial production.ODS pure aluminum was prepared by ball milling, sintering, hot extrusion and drawing with atomized pure aluminum powders. Relative density of sintered pure aluminum had reached 98.8%. And then relative density reached 100% by hot extrusion. The oxygen content of the powder increased by ball milling, which led to the increasing of the content of the dispersion particles. Also, the uniformity of dispersion particles increased by ball milling. Previous particle boundary is broken and the the uniformity of dispersion particles increased by hot extrusion and drawing. The dispersion particles in matrix is γ-Al2O3, which comfirmed by TEM diffraction pattern.The recrystallization which led to grain refining happened as a result of dislocation pileup by dispersion particles and nucleation. Cold drawing made the grain finer. The movement of grain boundaries were hindered by dispersion particles, as a result, the fine grain kept stable. The mean grain size of the annealed samples which was extruded and drawn to Φ2mm was about 1μm. The strength of samples annealed increased with the increasing of the extrusion and drawing deformation. The increasing of the strength came from the decreasing of the mean grain size and increasing of dispersion strengthening effect. By calculation, it can be comfirmed that dispersion strengthening is the main strengthening mechanisms. Tensile strength and yield strength of sample 2# which was drawn to Φ2mm and annealed were 188MPa and 172MPa, respectively. And elongation was 19%. The electric conductivity was 60.6%IACS.ODS 2024 aluminum alloy and 2A50 aluminum alloy were fabricated by powder metallurgy method. Relative density of sintered 2024 aluminum alloy prepared by elemental powders was 99.0%. The ultimate tensile strength and yield strength of the extruded samples with T6 heat treatment are 606 MPa and 469 MPa, respectively. The elongation was 10.3%. ODS 2024 aluminum alloy exhibits excellent high temperature strenghth and fatigue strength. Compared to 2A50 aluminum alloy wheel prepared by casting and forging, ODS 2A50 aluminum alloy wheel exhibits excellent mechanical properties. The ultimate tensile strength and yield strength are 520 MPa and 392 MPa, respectively. The elongation was 14.5%.ODS 7xxx aluminium alloy with 10wt% Zn and ODS 7055 aluminum alloy were fabricated by powder metallurgy method. Relative density of both aluminum alloy had reached above 99%. Temperature and time of solution treatment had little effect to the microstructure and properties of ODS 7xxx aluminum alloy. The ultimate tensile strength and yield strength of samples with 10wt% Zn by T6 heat treatment are 810 MPa and 770 MPa, respectively. The elongation was 8%. The reinforcing mechanismof the samples is precipitation strengthening, dispersion strengthening and fine crystal strengthening. Compared to traditional 7055 aluminum alloy, ODS 7055 aluminum alloy exhibits excellent mechanical properties. The ultimate tensile strength and yield strength are 744 MPa and 650 MPa, respectively. The elongation was 9.3%. |
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