Aging Time on the Microstructure and Mechanical Properties of A356 Alloy by Semi-solid Processing
An investigation was carried out to study the effects of aging time on the microstructure and mechanical properties of A356 alloy by semi-solid processing. The alloy was subjected to solution treatment for 4 h at 540 °C, artificial ageing was carried out at temperature (170 °C) and different time (0–24 h). The results revealed that the needle-shaped eutectic Si phase in as-cast ingot was transformed to globular shape compared with that by solution treatment. Meanwhile the Chinese script π-Fe(AlMgSiFe) phase was transformed to smaller and uniformly distributed β-Fe(AlFeSi) phase, the elongation increased obviously. With the increasing of aging time, the elongation decreased, and the ultimate tensile strength increased. When the aging time was 4 h, the alloy achieved the optimal mechanical properties. The micro-hardness was 121HV, ultimate tensile strength was 329 MPa, and the elongation was 15%. From the fracture morphology, the fracture for alloy aging for 4 h showed more dimples. With the increasing of aging time, the ultimate tensile strength and the elongation decreased.
KeywordsA356 alloy Semi-solid Aging time Microstructure Tensile properties
This work was supported by Beijing Municipal Science and Technology Commission (Z161100002116004) and the Beijing Lab project for modern transportation metallic materials and processing technology.
- 1.Menargues S, Martín E, Baile M T, et al. New short T6 heat treatments for aluminium silicon alloys obtained by semisolid forming, J. Materials Science and Engineering: A. 621 (2015) 236–242.Google Scholar
- 2.Burapa R, Janudom S, Chucheep T, et al. Effects of primary phase morphology on mechanical properties of Al–Si–Mg–Fe alloy in semi-solid slurry casting process, J. Transactions of nonferrous metals society of China. 20 (2010) 857–861.Google Scholar
- 3.Lashkari O, Ghomashchi R. Rheological behavior of semi-solid Al–Si alloys: Effect of morphology, J. Materials Science and Engineering: A. 454 (2007) 30–36.Google Scholar
- 4.Mao F, Yan G, Xuan Z, et al. Effect of Eu addition on the microstructures and mechanical properties of A356 aluminum alloys, J. Journal of Alloys and Compounds. 650 (2015) 896–906.Google Scholar
- 5.Sjölander E, Seifeddine S. The heat treatment of Al–Si–Cu–Mg casting alloys, J. Journal of Materials Processing Technology. 210(10) (2010) 1249–1259.Google Scholar
- 6.Dioni D, Cecchel S, Cornacchia G, et al. Effects of artificial aging conditions on mechanical properties of gravity cast B356 aluminum alloy, J. Transactions of Nonferrous Metals Society of China. 25(4) (2015) 1035–1042.Google Scholar
- 7.Patakham U, Limmaneevichitr C. Effects of iron on intermetallic compound formation in scandium modified Al–Si–Mg Alloys, J. Journal of Alloys and Compounds. 616 (2014) 198–207.Google Scholar
- 8.Taylor J A, Schaffer G B, St. John D H. The role of iron in the formation of porosity in Al–Si–Cu-based casting alloys: Part I. Initial experimental observations, J. Metallurgical and Materials Transactions A. 30(6) (1999) 1643–1650.Google Scholar
- 9.Gustafsson G, Thorvaldsson T, Dunlop G L. The influence of Fe and Cr on the microstructure of cast Al–Si–Mg alloys, J. Metallurgical Transactions A. 17(1) (1986) 45–52.Google Scholar
- 10.Li R X, Li R D, Zhao Y H, et al. Age-hardening behavior of cast Al–Si base alloy, J. Materials Letters. 58(15) (2004) 2096–2101.Google Scholar