Synergistically Improved Mechanical Properties and Thermal Conductivity of Hypoeutectic AlSiNiFeMg Alloy Prepared by Ultrasonic-assisted Casting

Abstract

We employed a melt ultrasonic treatment near the liquidus to prepare a high-thermal-conductivity Al-4Si-2Ni-0.8Fe-0.4Mg alloy. The influences of various ultrasonic powers on its microstructure, mechanical properties, and thermal conductivity were investigated. It is shown that near-liquidus ultrasonication significantly refines the alloy grains and eutectic structure, synergistically improving the alloy’s mechanical properties and thermal conductivity. Specifically, the grain size decreased by 84.5% from 941.4 to 186.2 µm. Increasing the ultrasonic power improved the thermal conductivity of the alloy slightly and significantly enhanced its mechanical properties. At an ultrasonic power of 2 100 W, the tensile strength, yield strength, elongation rate, and thermal conductivity were 216 MPa, 142 MPa, 6.3%, and 169 W/(m·k), respectively.

Keywords

Al-Si alloy / mechanical property / thermal conductivity / ultrasonic treatment / solidification / microstructure

References

[1] Qi M, Kang Y, Li J, et al. Improvement in Mechanical, Thermal Conductivity and Corrosion Performances of a New High-thermally Conductive Al-Si-Fe Alloy Through a Novel R-HPDC Process[J]. J. Mater. Process Technol., 2020: 279

[2] Zhang X, Zhou Y, Zhong G, et al. Effects of Si and Sr Elements on Solidification Microstructure and Thermal Conductivity of Al-Si-based Alloys[J]. J. Mater. Sci., 2022, 57(11): 6 428-6 444

[3] Kumar L, Jang J C, Yu H, et al. Effect of Secondary Phase on Mechanical and Thermal Conductivity of Al-Si-xFe-Mg-yCu-Mn Die Casting Alloys[J]. Mater. Lett., 2022: 314

[4] Gan JQ, Huang Y J, Wen C, et al. Effect of Sr Modification on Microstructure and Thermal Conductivity of Hypoeutectic Al-Si Alloys[J]. Trans. Nonferrous Met. Soc. China, 2020, 30(11): 2 879-2 890

[5] Gan J, Du J, Wen C, et al. The Effect of Fe Content on the Solidification Pathway, Microstructure and Thermal Conductivity of Hypoeutectic Al-Si Alloys[J]. Int. J. Metalcast, 2021, 16(1): 178-190

[6] Dutta B, Rettenmayr M. Effect of Cooling Rate on the Solidification Behaviour of Al-Fe-Si Alloys[J]. Mater. Sci. Eng, A, 2000, 283(1–2): 218-224

[7] Zhou Y, Zhang X, Zhong G, et al. Elucidating Thermal Conductivity Mechanism of Al-9Si Based Alloys with Trace Transition Elements (Mn, Cr, V)[J]. J. Alloys Compd., 2022: 907

[8] Chen JK, Hung HY, Wang CF, et al. Effects of Casting and Heat Treatment Processes on the Thermal Conductivity of an Al-Si-Cu-Fe-Zn Alloy[J]. Int. J. Heat Mass. Transfer., 2017, 105: 189-195

[9] Zhu X, Ai S, Lu X, et al. Thermal Conductivity of Closed-cell Aluminum foam Based on the 3D Geometrical Reconstruction[J]. Int. J. Heat Mass. Transfer., 2014, 72: 242-249

[10] Lin C, Wu SS, Zhong G, et al. Effect of Ultrasonic Vibration on Fe-containing Intermetallic Compounds of Hypereutectic Al-Si Alloys with High Fe Content[J]. Trans. Nonferrous Met. Soc. China, 2013, 23(5): 1 245-1 252

[11] Gao XP, Li XT, Qie XW, et al. Effect of High-intensity Ultrasound on Restraining Solute Segregation in Al-Si Alloy Casting Process[J]. Acta Phys. Sin., 2007, 56: 1 188-1 194