The Preparation And Study Of Properties For Cast Aluminum Alloy With High Strength And Electrical Conductivity

The status of Aluminum conductors'applications and research were described in the article. The applications of cast Aluminum alloy in power system were described too. The factors that affect its electrical conductivity and reinforcement methods were analyzed. The effects of optimal ratio of elements, the process of heat treatment and complex modification on the mechanical properties and electrical conductivity were studied deeply.The effect trends of elements'components(Silicon, Copper and Magensium) on electrical conductivity and mechanical properties of alloys were identified by orthogonal test to obtain the optimal components. Then, according to reference of Z1105 and Z1101A heat treatment and alloying elements' components in this experiment, T6 was established and the aging time was determined by single test. Finally, Sb and Zr were fused into alloys melts according to the principle of Aluminum alloys modification and grain refinement. These effects on the microstructure, mechanical properties and electrical conductivity of the alloys were investigated by OM, SEM, EDS, XRD, and EUMTS, etc. The mechanisms were also analyzed.There were three experiment results as felloys:Firstly, the tensile strength, the hardness and the electrical conductivity were affected most significantly respectively by Silicon, Magensium and Copper. The optimization of elements' components were cast state Al3.0Si1.5Cu0.6Mg and T6 state Al4.0Si1.0Cu0.6Mg. Secondly, the T6 heat treatment process of this test was identified as 525±5℃×6hâ†'180℃×10h. The mechanical properties and electrical conductivity were improved greatly after T6 treatment. The Al4.0Si0.5Cu0.6Mg(s-4) alloy's tensile strengthσb in cast state was 185MPa, the HBS hardness 73, and the electrical conductivity 24.1MS/m. However, they were respectively 338MPa, 112,26.3Ms/m after T6 and increased respectively by 83%,53%,9% than the cast alloys. Thirdly, the mechanical properties and electrical conductivity were improved greatly after complex modification. The Al4.0Si1.0Cu0.6Mg(x-2) alloy's tensile strengthσb in T6 state was 343Mpa, and the electrical conductivity 23.7MS/m. However, they were respectively 387MPa,26.1Ms/m after complex modification and increased respectively by 13% and 10%.There were two analysis results as felloys:on the one hand, the mechanical properties were improved greatly because the dispersion strengthening phase precipitated and impeded dislocation movement. Due to precipitation of solute atoms, the uniformity and purity of the substrate were increased and the lattice distortion and the probability of electron waves were reduced. Therefore, the electrical conductivity were improved greatly. On the other hand, the grains were refined and the eutectic Si phase was modificated after Al-Zr refinement and Al-Sb modification. Al3Zr particles refined grains by the peritectic reaction. Sb changed the eutectic Si particle into the lath-shaped oval by TPRE(twin plane regeneration stage). The mechanical properties and electrical conductivity of the alloys have reached the advanced level and met the needs of high strength and high electrical conductivity structural components after optimization of elements'components, complex modification and T6 heat treatment.