(華南理工大學(xué) 材料科學(xué)與工程學(xué)院，廣州 510640)
摘 要: 研究了Mg、Zn、Cu三種合金元素對(duì)Al-7Si-0.8Fe導(dǎo)電和抗退火軟化性能的影響，并分析其影響機(jī)理。合金元素加入后合金的導(dǎo)電率均有不同程度降低，低溫退火提升合金的導(dǎo)電率，其中，含Mg合金的導(dǎo)電率提升最為顯著，導(dǎo)電率可達(dá)22.9 MS/m，而含Zn、Cu合金的導(dǎo)電率提升幅度較小。Mg顯著提升的硬度和抗拉強(qiáng)度，經(jīng)退火后，合金發(fā)生不同程度軟化，Cu添加后合金的退火軟化最為顯著，而Mg則表現(xiàn)出優(yōu)異的抗退火軟化特性，硬度和抗拉強(qiáng)度可達(dá)79 HB和266 MPa。Mg可顯著細(xì)化鑄態(tài)合金中的共晶Si相，低溫退火過(guò)程中，基礎(chǔ)合金及含Zn和Cu的合金中基體中均有明顯的Si相析出，而在含Mg合金中生成細(xì)小彌散的Mg2Si相，保證其優(yōu)異的抗退火軟化特性。
關(guān)鍵字: 鑄造鋁合金；導(dǎo)電、導(dǎo)熱性能；力學(xué)性能；抗退火軟化特性
（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
