Cu含量对Al-12Si合金组织结构及导热性能的影响
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摘要
采用熔铸工艺制备了不同Cu含量(0.03%～4.2%)的Al-12Si-xCu-0.6Mg合金试样,分析Cu含量对Al-Si合金组织结构、力学性能与导热性能的影响。结果表明,随着Cu含量从0.03%增加到4.2%,Al-12Si-xCu-0.6Mg合金强度由212.3 MPa提高到285.3MPa,但热导率由152W/(m·K)降低到119W/(m·K)。另外,随着Cu含量增加,合金中初生α-Al相明显细化,从发达树枝晶向细小圆整等轴晶转化,共晶Si相晶粒尺寸逐渐增大;分散的块状α-Al相会造成电子传导通道的断裂,粗大的共晶Si提高电子运动过程中的散射概率,降低自由电子的平均自由程,从而导致合金导热性能下降。
The Al-12 Si alloys with different Cu contents were prepared by metal mold casting.The effects of Cu on the mechanical properties and thermal conductivity of Al-12Si-xCu-0.6Mg alloys were investigated.The results reveal that the mechanical properties are enhanced greatly as the Cu content increase.With the increase of Cu content,the strength of Al-12Si-xCu-0.6Mg alloy is increased from 212.3MPa to 285.3MPa,while the thermal conductivity is decreased from 152W/(m·K)to 119W/(m·K).Microscopic analysis reveals that with the Cu content increase,α-Al is refined gradually from the developed dendrite to fine equiaxed grain and eutectic Si phase is coarsened.The dispersed blockα-Al cause the fracture of the electronic thermal conduction channel of the alloy,and the coarse eutectic Si can increase the scattering of electron conduction,resulting in a decrease of the thermal conductivity of the alloy.
The Al-12 Si alloys with different Cu contents were prepared by metal mold casting.The effects of Cu on the mechanical properties and thermal conductivity of Al-12Si-xCu-0.6Mg alloys were investigated.The results reveal that the mechanical properties are enhanced greatly as the Cu content increase.With the increase of Cu content,the strength of Al-12Si-xCu-0.6Mg alloy is increased from 212.3MPa to 285.3MPa,while the thermal conductivity is decreased from 152W/(m·K)to 119W/(m·K).Microscopic analysis reveals that with the Cu content increase,α-Al is refined gradually from the developed dendrite to fine equiaxed grain and eutectic Si phase is coarsened.The dispersed blockα-Al cause the fracture of the electronic thermal conduction channel of the alloy,and the coarse eutectic Si can increase the scattering of electron conduction,resulting in a decrease of the thermal conductivity of the alloy.
引文
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[2]黄晓锋,田载友,朱凯,等.压铸铝合金及压铸技术的研究进展[J].热加工工艺,2008,37(17):137-141.
[3]陈文松.过共晶Al-Si合金性能和细化工艺概述[J].热加工工艺,1998(6):44-46.
[4] CHOI S W,CHO H S,KUMAI S.Effect of the precipitation of secondary phases on the thermal diffusivity and thermal conductivity of Al-4.5Cu alloy[J].Journal of Alloys&Compounds,2016,688:897-902.
[5] KIM Y M,CHOI S W,HONG S K.The behavior of thermal diffusivity change according to the heat treatment in Al-Si binary system[J].Journal of Alloys&Compounds,2016,687:54-58.
[6]王剑,曹东.高导热共晶Al-Si合金的制备及其性能[J].特种铸造及有色合金,2018,38(4):441-445.
[7]张建新,高爱华.改善铝合金导热性能途径的初探与分析[J].铸造技术,2004,25(9):719-721.
[8] RANA R S,PUROHIT R,DAS S.Reviews on the influences of alloying elements on the microstructure and mechanical properties of aluminum alloys and aluminum alloy composites[J].International Journal of Scientific and Research Publications,2012,2(6):1-7.
[9] CHEN J K,HUNG H Y,WANG C F,et al.Effects of casting and heat treatment processes on the thermal conductivity of an Al-SiCu-Fe-Zn alloy[J].International Journal of Heat&Mass Transfer,2017,105:189-195.
[10] CHEN J K,HUNG H Y,WANG C F,et al.Thermal and electrical conductivity in Al-Si/Cu/Fe/Mg binary and ternary Al alloys[J].Journal of Materials Science,2015,50(16):5 630-5 639.
[11] OLAFSSON P,SANDSTROM R,KARLSSON6)A.Comparison of experimental,calculated and observed values for electrical and thermal conductivity of aluminium alloys[J].Journal of Materials Science,1997,32(16):4 383-4 390.
[12]牛艳萍,赵禹凯,王顺成,等.Si含量对Al-Si-Mg合金铸造流动性、热导率和力学性能的影响[J].铸造,2016,65(4):366-370.