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http://dx.doi.org/10.7777/jkfs.2019.39.2.26

Mechanical Characteristics and Microstructures of Hypereutectic Al-17Si-5Fe Extruded Alloys Prepared by Rapid Solidification Process  

KIM, Tae-Jun (Department of Ferrous alloy, Moscow National University of Science and Technology)
LEE, Se-dong (Department of Metallurgical and Materials Engineering, Gyeongsang National Univ.)
BECK, Ah-Ruem (Department of Metallurgical and Materials Engineering, Gyeongsang National Univ.)
KIM, Duck-Hyun (Department of Metallurgical and Materials Engineering, Gyeongsang National Univ.)
LIM, Su-Gun (Department of Metallurgical and Materials Engineering, Gyeongsang National Univ.)
Publication Information
Journal of Korea Foundry Society / v.39, no.2, 2019 , pp. 26-31 More about this Journal
Abstract
In this study, the mechanical characteristics and microstructure of hypereutectic Al-17Si-5Fe extruded alloys prepared by a rapid solidification process (RSP) were investigated. The hypereutectic Al alloy was fabricated by means of RSP and permanent casting. For RSP, the Al alloy melted at $920^{\circ}C$, cooling the specimens at a rate of $10^6^{\circ}C/s$ when the RSP was used, thus allowing the refining of primary Si particles more than when using permanent casting, at a rate of about 91%. We tested an extrusion RSP billet and a permanent-cast billet. Before the hot-extrusion process, heating to $450^{\circ}C$ took place for one hour. The samples were then hotextruded with a condition of extrusion ratio of 27 and a ram speed of 0.5 mm/s. Microstructural analyses of the extruded RSP method and the permanent casting method were carried out with OM and SEM-EDS mapping. The mechanical properties in both cases were evaluated by Vickers micro-hardness, wear resistance and tensile tests. It was found that when hypereutectic Al-17Si-5Fe alloys were fabricated by a rapid solidification method, it becomes possible to refine Si and intermetallic compounds. During the preparation of the hypereutectic Al-17Si-5Fe alloy by the rapid solidification method, the pressure of the melting crucible was low, and at faster drum speeds, smaller grain alloy flakes could be produced. Hot extrusion of the hypereutectic Al-17Si-5Fe alloy during the rapid solidification method required higher pressure levels than hot extrusion of the permanent mold-casted alloy. However, it was possible to produce an extruded material with a better surface than that of the hot extruded material processed by permanent mold casting.
Keywords
Rapid Solidification process; Hypereutectic Al alloy; Hot- extruded; Amorphous; Microstructure;
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  • Reference
1 Materials Park, ASM Handbook Volume 2: Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM International OH (1990).
2 J. S. Thompson, J. Inst. Metals ,"A study of process variables in the production of aluminium powder by atomization", 74 (1948) 101.
3 P. Furrer and H. Warlomont, Z. Met alk. , "Microstructure and properties of aluminium alloys after rapid solidification. Il. Extension of solid solubilitly influence of thermal treatments, mechanical properties", 62 (1971) 100.
4 Transmet Corp., Pamphlet : "Transmet Facilities and Capabilities" OH (1983).
5 Jeong IS, Master's thesis, Graduate school of Gyeongsang National University, "Microstructure and mechanical properties of CNT/AZ31 composite prepared by mechanical alloying" (2011) 13.
6 Park JS, Master's thesis, Graduate school of Inha University, "A study on the mechanical and thermal properties of spray-cast hypereutectic Al-Si-Fe alloys" (2006)
7 Jeong YS and Lim SG, J. Kor. Inst. Met. & Mater, "Fabrication of splat quenched Al 7075-Mn extrusions and effect of manganese on the aging behavior", 38 (2001) 693-698.
8 Kim SJ and Lim SG, J. Kor. Inst. Met. & Mater, "Effect of Zr on Aging Behavior and Mechanical Properties of Splat Quenched and Extruded Al7075 - 2wt.% Mn Alloy", 39 (2009) 50-58.
9 J.L. Jorstad, "Temperature Effects on the fatigue behavior of an aluminium-silicon alloy, 92 (1984) 573.