【作者】 史霞；

【导师】 姚三九；

【作者基本信息】 武汉理工大学 ， 材料加工工程， 2010， 硕士

【摘要】 本文介绍了铝导体的应用研究现状及铸造铝合金在电力系统中的应用,分析了铸造铝合金电导率的影响因素和强化方法,研究了合金元素优化配比、热处理工艺和复合变质对铸造铝合金力学性能和电导率的影响。首先采用正交试验,找出合金元素(Si、Cu、Mg)对电导率和力学性能的影响趋势,得出高力学性能和高电导率的最优选择。然后参照ZL105及ZL101A的热处理规范,结合本次试验的合金成分,采用T6处理,并用单项试验方法确定时效时间。最后根据变质与细化原理,通过向合金添加铝锑和铝锆中间合金的方法,进行复合变质处理。利用金相显微镜,扫描电镜、能谱分析,XRD,D60K型导电仪及力学性能测试等手段,研究合金元素、T6处理和复合变质对合金的显微组织、力学性能和电导率的影响,并分析其作用机理。试验结果表明：(1)正交试验分析得出：Si、Mg、Cu元素分别对合金的强度、硬度和电导率的影响最显著。成分优化选择铸态为Al3.0Si1.5Cu0.6Mg,T6态为A14.0Si1.0Cu0.6Mg。(2)本次试验的T6热处理工艺确定为：525±5℃×6h→180℃×10h。经T6处理后,合金力学性能和电导率均得到提高。Al4.0Si0.5Cu0.6Mg(s-4)合金铸态时抗拉强度σb为185MPa、布氏硬度HBS为73,电导率σ为24.1Ms/m,T6后抗拉强度σb为338MPa、布氏硬度HBS为112,电导率。为26.3Ms/m,比铸态分别提高了83%、53%、9%。(3)复合变质后,合金力学性能和电导率也明显提高,A14.0Si1.0Cu0.6Mg(x-2)合金未复合变质前的抗拉强度σb为343MPa、电导率。为23.7Ms/m,复合变质后,抗拉强度σb为387MPa、电导率。为26.1Ms/m,比复合变质前分别提高了13%、10%。分析结果表明：(1)合金力学性能的提高是因为强化相的弥散析出阻碍了位错运动；合金电导率的提高是因为溶质原子的均匀析出增加了基体的均匀性和纯净度,减少了晶格畸变和电子波的散射几率。(2)复合变质使α(Al)晶粒细化、共晶Si变质,是细化剂Al-Zr和变质剂Al-Sb共同作用的结果。Al3Zr粒子通过包晶反应细化了晶粒；Sb按TPRE机制使共晶Si由板条状变为粒状。合金经成分优化、复合变质和T6处理后,力学性能和电导率已经达到国内同类合金的领先水平,可以满足高强度高电导率电讯结构部件的需要。更多还原

【Abstract】 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℃×6h→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.更多还原