In this study, the effects of pouring temperature (solid fraction of primary particles) on the structure and liquid segregation behaviour of a cup-shaped semi-solid rheocast processed casting made from the A356 aluminium alloy were investigated. Results showed that the solid fraction of primary particles at the bottom of the castings was greater than in other parts of the castings, and the highest liquid segregation occurred in the mid-height (wall) of the castings. Liquid segregation was increased with an increase in the initial solid fraction of primary particles. The critical solid fraction at pouring for minimum liquid segregation was found to be approximately 25%.
This paper is part of a thematic issue on Light Alloys.
FlemingsMC.Behaviour of metal alloys in the semisolid state. Metall Trans. 1991;22:957–981.
2.
KirkwoodDH.Semisolid metal processing. Int Mater Rev. 1994;39:173–189.
3.
FanZ.Semisolid metal processing. Int Mater Rev. 2002;47:49–85.
4.
PatelJB, LiuYQ, ShaoG, Rheo-processing of an alloy specifically designed for semi-solid metal processing based on the Al-Mg-Si system. Mater Sci Eng. 2008;476:341–349.
5.
YurkoJA, MartinezRA, FlemingsMC.Commercial development of the semi-solid rheocasting (SSR tm) process. Metall Sci Technol. 2003;21:10–15.
6.
ZhangD, DongHB, AtkinsonHV.What is the process window for semi-solid processing?Metall Mater Trans A. 2016;47:1–5.
7.
NafisiS, GhomashchiR.Semi-solid processing of aluminum alloys. Switzerland: Springer; 2016.
8.
ReisiM, NiroumandB.Effects of stirring parameters on rheocast structure of Al-7.1wt%Si alloy. J Alloys Compd. 2009;470:413–419.
9.
ReisiM, NiroumandB.Growth of primary particles during secondary cooling of a rheocast alloy. J Alloys Compd. 2009;475:643–647.
10.
AtkinsonHV.Modelling the semi-solid processing of metallic alloys. Prog Mater Sci. 2005;50:341–412.
11.
FuJ, WangK, LiX, Microstructure evolution and thixoforming behavior of 7075 aluminum alloy in the semi-solid state prepared by RAP method. Int J Min Met Mater. 2016;23:1404–1415.
12.
YongnanC, ChuangL, FengyingZ, Effect of temperature on segregation and deformation mechanism of α+Ti2Cu alloy during semi-solid forging. Rare Met Mater Eng. 2015;44:1369–1373.
13.
ZhangK, YuH, LiuJ, Microstructure and property of a functionally graded aluminum silicon alloy fabricated by semi-solid backward extrusion process. Mater Sci Eng. 2015;624:229–238.
14.
VieiraEA, FerranteM.Prediction of rheological behaviour and segregation susceptibility of semi-solid aluminium–silicon alloys by a simple back extrusion test. Acta Mater. 2005;53:5379–5386.
15.
SeoPK, YounSW, KangCG.The effect of test specimen size and strain-rate on liquid segregation in deformation behavior of mushy state material. J Mater Process Technol. 2002;130–131:551–557.
16.
KhosravaniA, AashuriH, DavamiP, Liquid segregation behavior of semi-solid AZ91 alloy during back extrusion test. J Alloys Compd. 2009;477:822–827.
17.
CaiB, KaragaddeS, RowleyD, Time-resolved synchrotron tomographic quantification of deformation-induced flow in a semi-solid equiaxed dendritic Al–Cu alloy. Scr Mater. 2015;103:69–72.
18.
VieiraEA, KliaugaAM, FerranteM.Microstructural evolution and rheological behaviour of aluminium alloys A356, and A356 + 0.5% Sn designed for thixocasting. J Mater Process Technol. 2004;155–156:1623–1628.
19.
KoppR, WinningG, KallweitJ, Comparison of thixocasting and thixoforging using a unique demonstrator part. Proceedings of the 6th International Conference on ‘Semi-Solid Processing of Alloys and Composites’, Turin, Italy; 2000. p. 687.
20.
Wei-MinM, QiuZ, Da-PingZ.Rheo-squeeze casting of semi-solid A356 aluminum alloy slurry. Trans Nonferr Met Soc China. 2010;20:1769–1773.
21.
YurkoJ, BoniR.SSR semi-solid rheocasting. La Metall Italiana. 2006;3:35–41.
22.
YurkoJ, MartinezR, FlemingsM.The use of semi-solid rheocasting (SSR) for aluminum automotive castings. Proceedings of the SAE 2003 world congress, Detroit, USA, 2003, SAE Technical Paper 2003-01-0433.
SadoughSA, RahmaniMR, PouyafarV.Rheological behavior, microstructure and hardness of A356 aluminum alloy in semisolid state using backward extrusion process. Trans Nonferr Met Soc China2010;20:s906–s910.
25.
BurapaR, JandomS, ChucheepT, Effects of primary phase morphology on mechanical properties of Al-Si-Mg-Fe alloy in semi-solid slurry casting process. Trans Nonferrous Met Soc China. 2010;20:s857–s861.
26.
KirkwoodDH, SueryM, KapranosP, Semi-solid processing of alloys. New York ( NY): Springer; 2009.
27.
WannasinJ, JanudomS, RattanochaikulT, Research and development of gas induced semi-solid process for industrial applications. Trans Nonferrous Met Soc China. 2010;20:s1010–s1015.
