(华南理工大学 材料科学与工程学院，广州 510640)
摘 要: 研究了Mg、Zn、Cu三种合金元素对Al-7Si-0.8Fe导电和抗退火软化性能的影响，并分析其影响机理。合金元素加入后合金的导电率均有不同程度降低，低温退火提升合金的导电率，其中，含Mg合金的导电率提升最为显著，导电率可达22.9 MS/m，而含Zn、Cu合金的导电率提升幅度较小。Mg显著提升的硬度和抗拉强度，经退火后，合金发生不同程度软化，Cu添加后合金的退火软化最为显著，而Mg则表现出优异的抗退火软化特性，硬度和抗拉强度可达79 HB和266 MPa。Mg可显著细化铸态合金中的共晶Si相，低温退火过程中，基础合金及含Zn和Cu的合金中基体中均有明显的Si相析出，而在含Mg合金中生成细小弥散的Mg2Si相，保证其优异的抗退火软化特性。
关键字: 铸造铝合金；导电、导热性能；力学性能；抗退火软化特性
（School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China）
Abstract:The effects of Mg, Zn and Cu alloy elements on the electrical conductivity and anti-annealing softening property of Al-7Si-0.8Fe base alloy were studied in the present study. The influence mechanism was deeply discussed. The electrical conductivity of the base alloy decreases to vary degrees after the addition of alloy elements. The electrical conductivities of the all alloys increase after being low-temperature annealed. The electrical conductivity of Mg-containing alloy remarkably increases to 22.9 MS/m. Relatively, the improvement of electrical conductivity of Zn or Cu-containing alloys is small. Mg addition can significantly improve the hardness and tensile strength by about 34.3% and 20.4% compared with the base alloy. Annealing softening occurs for the all alloys to different degrees. Mg addition shows the lowest annealing softening and high anti-annealing softening properties. The hardness and tensile strength of as-annealed Al-7Si-0.8Fe-0.5Mg alloy are 79 HB and 266 MPa, respectively. Mg addition can significantly refine the eutectic Si phase in the as-cast alloy. During the low-temperature annealing process, small Si particles obviously precipitate of in the base alloy and Zn or Cu-containing alloys. However, fine dispersion of Mg2Si phase precipitate in the Mg-containing alloy, ensuring the excellent resistance to annealing softening.
Key words: casting aluminum alloy; electrical and thermal conductivity; mechanical property; anti-annealing softening property
