Morphological Analysis Of Ssm Al-4.5 Wt.% Cu Measured By The Rheocast Quality Index

There is a direct relationship between grain size obtained from macrostructure characterisation and the globule size and shape factor, obtained from microstructure characterisation: the smaller the grain size, the smaller the globule size and shape factor. Due to this a rheocast quality index (RQI = globulesize/(grainsize × shapefactor)) was used to evaluate the Al-4.5 wt.% Cu alloy produced by strain induced melting activation (SIMA). The structure that presents the smallest grain size, the smallest shape factor, and the most homogeneous and globular size of the primary phase, has the best RQI and consequently the best behaviour in the semi-solid forming. Four different as-cast structures were cold rolled to obtain 20 and 40% deformation and were partially melted at 635°C at holding times of 5min. Both, macro- and microstructure were characterised. © 2003 Elsevier Science B.V. All rights reserved.143-1441195201Tzimas, E., Zavaliangos, A., Lawley, A., (1998) Proceedings of the Fifth Conference on Semi-solid Processing of Alloys and Composites, pp. 345-352. , Golden, CO, USALeathan, A.G., Lawley, A., (1993) Int. J. Powder Metall., 29 (4), pp. 321-329Flemings, M.C., (1991) Metall. Trans. A, 22, pp. 957-981Kirkwood, D.H., (1994) Int. Mater. Rev., 39 (5), pp. 173-189Ito, Y., Flemings, M.C., Cornie, J.A., (1992) Proceedings of the TMS Symposium on Nature and Properties of Semi-solid Materials, pp. 3-17. , San Diego, CA, USAApaydin, N., Prabhakar, K.V., Dohert, R.D., (1980) Mater. Sci. Eng., 46, pp. 145-150Niroumandi, B., Xia, K., (2000) Mater. Sci. Eng. A, 283, pp. 70-75Loué, W.R., Suéry, M., (1995) Mater. Sci. Eng. A, 203, pp. 1-13Salvo, L., Loué, W.R., Suéry, M., (1995) ISIJ Int., 35 (6), pp. 798-804Bartos-Tausig, G., Xia, K., (1996) Mater. Sci. Forum, 217-222, pp. 323-328Paes, M., Herzig, S., Zoqui, E.J., (2000) Proceedings of the Sixth Conference on Semi-solid Processing of Alloys and Composites, pp. 693-699. , Turim, ItalyZoqui, E.J., Robert, M.H., (2001) J. Mater. Process. Technol., 109, pp. 215-219Zoqui, E.J., Paes, M., Essadiqi, E., (2002) J. Mater. Process. Technol., 120 (1-3), pp. 365-373Zoqui, E.J., Shehata, M.T., Paes, M., Kao, V., Essadiqi, E., (2002) J. Mater. Sci. Eng. A, 325, pp. 38-5

Novas Tecnologias De Manufatura De Metais No Estado Semi-sólido

Rheofoundry has been developing in Brazil since 1985, based on work developed at the Faculdade de Engenharia Mecânica of UNICAMP, and anticipates further growth within the coming years. The use of semi-solid technology drastically reduces operational and capital costs in metal manufacture.52452259361Flemings, M.C., Behavior of Metal Alloys in the Semi-solid State (1991) Metallurgical Transactions A, 22 A, p. 957Young, K.P., Semi-solid Metal Casting and Forging (1988) Metals Handbook, 15, p. 327. , ASM, 9a. e

Effect Of Silicon On The Thixoformability Of Al-si-cu Alloys

The thixoformability of new Al-Si-Cu alloys was evaluated and characterized by their microstructural and rheological behavior. Alloys Al1Si2.6Cu, Al2Si2.6Cu, Al4Si2.6Cu, and Al7Si2.6Cu were produced with the addition of Al5Ti1B grain refiner alloy. The materials were heat treated under two controlled conditions: holding times of 0, 30, 90, and 210 s and solid fraction of 45 and 60%. The evaluation of the microstructure and semisolid behavior was characterized by globule size, shape factor (SF), minimum stress to flow, maximum stress, and apparent viscosity. The heat treatment times promoted the globularization of solid phase particles to achieve better apparent viscosity results for the alloys treated for 210 s. Both 45 and 60% solid fraction showed no significant differences in terms of SF, but the alloys containing lower solid fraction showed better performance for apparent viscosity. Better working ranges for these new Al-Si-Cu alloys were determined reaching average strain of 0.5 MPa and apparent viscosity of 105 Pa s. © 2014 ASM International.23931653179Spencer, D.B., Mehrabian, R., Flemings, M.C., Rheological Behavior of Sn-15 Pct Pb in the Crystallization Range (1972) Metall. Trans., 3 (7), pp. 1925-1932. , 10.1007/BF02642580Flemings, M.C., Behavior of Metal Alloys in the Semisolid State (1991) Metall. Trans. B, 22 (3), pp. 269-293. , 10.1007/BF02651227Kirkwood, D.H., Semisolid Metal Processing (1994) Int. Mater. Rev., 39 (5), pp. 173-189. , 10.1179/imr.1994.39.5.173Tsuchiya, M., Ueno, H., Takagi, I., Research of Semisolid Casting of Iron (2003) JSAE Rev., 24 (2), pp. 205-214. , 10.1016/S0389-4304(03)00013-4Rassili, A., Atkinson, H.V., A review on Steel Thixoforming (2010) Trans. Nonferrous Met. Soc. China, 20 (3), pp. 1048-1054. , 10.1016/S1003-6326(10)60629-2Xiao, Z.H., Luo, J.R., Wu, S.S., Li, D.N., Mao, Y.W., Song, X.J., Study on a Semisolid Rheo-diecasting Process with AZ91D Alloy Slurry (2004) J. Mater. Eng. Perform., 13 (1), pp. 60-63. , 10.1361/10599490417641Fan, Z., Development of the Rheo-diecasting Process for Magnesium Alloys (2005) Mater. Sci. Eng. A, 413-414, pp. 72-78. , 10.1016/j.msea.2005.09.038Loué, W.R., Suéry, M., Microstructural Evolution during Partial Remelting of Al-Si-7Mg Alloys (1995) Mater. Sci. Eng. A, 203 (1-2), pp. 1-13. , 10.1016/0921-5093(95)09861-5Sigworth, G.K., Rheological Properties of Metal Alloys in the Semisolid State (1996) Can. Metall. Q., 35 (2), pp. 101-122. , 10.1179/cmq.1996.35.2.101Liu, D., Atkinson, H.V., Kapranos, P., Jirattiticharoean, W., Jones, H., Microstructural Evolution and Tensile Mechanical Properties of Thixoformed High Performance Aluminium Alloys (2003) Mater. Sci. Eng. A, 361 (1-2), pp. 213-224. , 10.1016/S0921-5093(03)00528-8Atkinson, H.V., Alloys for Semisolid Processing (2013) Solid State Phenom., 192-193, pp. 16-27Zoqui, E.J., Shehata, M.T., Paes, M., Kao, V., Es-Sadiqi, E., Morphological Evolution of SSM A356 during Partial Remelting (2002) Mater. Sci. Eng. A, 325 (1-2), pp. 38-53. , 10.1016/S0921-5093(01)01401-0Paes, M., Zoqui, E.J., Semisolid Behavior of New Al-Si-Mg Alloys for Thixoforming (2005) Mater. Sci. Eng. A, 406 (1-2), pp. 63-73. , 10.1016/j.msea.2005.07.018Zoqui, E.J., Naldi, M.A., Evaluation of the Thixoformability of the A332 Alloy (Al-9.5 wt%Si-2.5 wt%Cu) (2011) J. Mater. Sci., 46 (23), pp. 7558-7566. , 10.1007/s10853-011-5730-2Zoqui, E.J., Torres, L.V., Evaluation of the Thixoformability of AA7004 and AA7075 Alloys (2010) Mater. Res., 13 (3), pp. 305-318. , 10.1590/S1516-14392010000300006Standard Test Methods for Determining Average Grain Size, pp. 1-26. , ASTM E112 - 96, ASTM InternationalLaxmanan, V., Flemings, M.C., Deformation of Semisolid Sn-15 Pct Pb Alloy (1980) Metall. Trans. A, 11 (12), pp. 1927-1937. , 10.1007/BF02655112Proni, C.T.W., D'Ávila, M.A., Zoqui, E.J., Thixoformability Evaluation of AA2011 and AA2014 Alloys (2013) Int. J. Mater. Res., 104 (12), pp. 1182-1196. , 10.3139/146.110983Liu, D., Atkinson, H.V., Jones, H., Thermodynamic Prediction of Thixoformability in Alloys Based on the Al-Si-Cu and Al-Si-Cu-Mg Systems (2005) Acta Mater., 53 (14), pp. 3807-3819. , 10.1016/j.actamat.2005.04.028Roca, A.S., Fals, H.D.C., Pedron, J.A., Zoqui, E.J., Thixoformability of Hypoeutectic Gray Cast Iron (2012) J. Mater. Process. Technol., 212 (6), pp. 1225-1235. , 10.1016/j.jmatprotec.2012.01.012Birol, Y., Effect of Silicon Content in Grain Refining Hypoeutectic Al-Si Foundry Alloys with Boron and Titanium Additions (2012) Mater. Sci. Technol., 28 (4), pp. 385-389. , 10.1179/1743284711Y.0000000049Rooy, E.L., (1992) Aluminium and Aluminium Alloys, Casting, ASM Handbook, pp. 1622-1696. , 15 ASM International Materials Park, OHGuo, H.M., Luo, X.Q., Zhang, A.S., Yang, X.J., Isothermal Coarsening of Primary Particles during Rheocasting (2010) Trans. Nonferrous Met. Soc. China, 20 (8), pp. 1361-1366. , 10.1016/S1003-6326(09)60305-8Liu, T.Y., Atkinson, H.V., Kapranos, P., Kirkwood, D.H., Hogg, S.C., Rapid Compression of Aluminium Alloys and its Relationship to Thixoformability (2003) Metall. Mater. Trans. A, 34 (7), pp. 1545-1554. , 10.1007/s11661-003-0266-

Evaluation Of The Thixoformability Of The A332 Alloy (al-9.5 Wt%si-2.5 Wt%cu)

The main purpose of this article is to develop and/or use a commercial conventional low-cost raw material as thixoforming material in order to diminish the costs of the thixoforming process. Semi-solid technology usually uses aluminium low-silicon alloys such A356 (Al- 7.0 wt%Si) as raw materials. High silicon content alloys with a quasi-eutectic composition diminish the semi-solid range, making it difficult to control the thixoforming temperature, although present excellent mechanical properties. This article reports on the semi-solid behaviour of Al-9.5 wt%Si-2.5 wt%Cu (A332). Thermo-Calc simulations and experimental DSC techniques were used to map the temperature transition from solid to liquid in order to achieve the best semi-solid behaviour and hence the best thixoforming temperature. Samples were reheated at three temperatures to 30, 45 and 60% of the solid fraction applying holding times of 0, 30, 90 and 210 s. The morphological evolution and semi-solid behaviour of the samples at these temperatures were determined via the fixed platen compression test. The structure showed the best semi-solid behaviour at 572 °C, with an apparent viscosity of up to 1.5 × 105 Pa s. The results indicated that the semi-solid behaviour of the commertial Al-9.5 wt%Si- 2.5 wt%Cu alloy is similar to that of the alloy A356. Despite its large dendritic structure it is possible, with the correct combination of temperature and time, to use this alloy as raw material for the thixoforming process. Furthermore, semi-solid parts can be produced by thixoforging using this low-cost material without any special preparation. © Springer Science+Business Media, LLC 2011.462375587566Flemings, M.C., Riek, R.G., Young, K.P., (1976) Mater Sci Eng, 25, p. 103Hirt, G., Khizhnyakova, L., Baajou, R., Knauf, F., Koop, R., (2009) Thixoforming, p. 18. , Hirt G, Kopp R (eds, Wiley-VCHR, WeinheimUdvardy, S., (2001) Science and Technology of Semisolid Metal Processing, pp. 6/1. , Figueiredo A (ed. North American Die Casting Association, WorcesterPaes, M., Zoqui, E.J., (2005) Mater Sci EngA, 406 (1-2), p. 63Young-Dong, K., Zin-Hyoung, L., (2003) Mater Sci Eng A, 360, p. 372Nafisi, S., Ghomashchi, R., (2006) J Mater Sci, 41, p. 7954. , doi: 10.1007/s10853-006-0866-1Legoretta, E.C., Atkinson, H.V., Jones, H., (2008) J Mater Sci, 43 (16), p. 5456. , doi:10.1007/s10853-008-2829-1Zhang, B., Cui, J., Lu, G., (2003) Mater Sci Eng A, 355, p. 325Zoqui, E.J., Gracciolli, J.I., Lourençato, L.A., (2008) J Mater Process Technol, 198, p. 155Zoqui, E.J., Lourençato, L.A., Benati, D.M., (2008) Diffus Defect Data B, 517, pp. 141-143Laxmanan, V., Flemings, M.C., (1980) Metall Trans A 11A, 1927Liu, T.Y., Atkinson, H.V., Kapranos, P., Kirkwood, D.H., Hogg, S.C., (2003) Metall Mater Trans A, 34 A, p. 1545Liu, D., Atkinson, H.V., Jones, H., (2005) Acta Mater, 53, p. 3807Elsebaie, O., Samuel, A.M., Samuel, F.H., (2011) J Mater Sci, 46 (9), p. 3027. , doi:10.1007/s10853-010-5181-

Characterization Of The Microstructure And Rheological Behavior Of Al-4wt%si-2.5wt%cu Alloy Produced By Direct Chill Casting And Electromagnetic Stirring

This work involved an evaluation of a Al-4wt%Si-2.5wtCu alloy to be used as raw materials in the thixoforming process. The alloy was produced by direct casting under electromagnetic stirring to obtain ingots of 250 mm length and 30 mm diameter. The alloy was analyzed to determine their morphology and rheological behavior in the semi-solid range. The tests included characterization of the microstructural evolution by subjecting them to re-heating treatment in two conditions of solid fractions, 45% and 60%, for 0, 30, 90 and 210 s. A compression testing device designed specifically to evaluate semi-solid materials was used to determine the rheological behavior, and the tests were performed at the same heating rate and hold times to determine the apparent viscosity. The use of electromagnetic stirring to produce the raw material was effective in producing alloy with very small grain/primary particle sizes (80 up to 120 μm). Based on the morphological evolution in the semi-solid state, the alloy showed only minor variations in grain/primary particle size and surface factor (SF) as a function of the different globularization heat treatment times, suggesting that all these alloys are suitable for production. The Al-4.0wt%Si-2.5wt%Cu alloy with 45% solid fraction presented apparent viscosity about 1.5 x106 Pa.s. © (2013) Trans Tech Publications, Switzerland.192-193142148Figueredo, A., (2001) Science and Technology of Semi-solid Metal Processing, , Worcester Polytechnic Institute Worcester, USAAtkinson, H.V., Modeling the Semi-solid Processing of Metallic Alloys (2005) Progress in Materials Science, 50, pp. 341-412Garat, M., Maenner, L., Sztur, C.H., State of the Art of Thixocasting (2000) Proceedings of the 6th International Conference on the Semi-solid Processing of Alloys and Composites, pp. 187-194. , in: TurinYoung, K., Eisen, P., SSM (Semi-solid metal) Technological Alternatives for Different Applications (2000) Proceedings of the 6th International Conference on the Semi-solid Processing of Alloys and Composites, pp. 97-102. , in: TurinLaxmanan, V., Flemings, M.C., Deformation of Semi-solid Sn-15%Pb Alloy (1980) Metallurgical Transactions A, 11, pp. 1927-1937Paes, M., Zoqui, E.J., Robert, M.H., Effect of macrostructure and microstructure on the viscosity of the A356 alloy in the semi-solid state (2004) Journal of Materials Processing Technology, 153-154 (1-3), pp. 300-30

Rheological Behaviour And Microstructural Evolution Of Semi-solid A356 Alloy Produced By Different Routes

Different techniques used to produce semi-solid alloys can result in different structures in the material and, therefore, in distinct rheological behaviours which determine its thixo-forming ability. Suitable raw materials to be used for SSM forming must present non-dendritic, very fine or fragmented structure in order to globularize without excessive agglomeration when re-heated to the semi-solid state. This work analyses the influence of raw material production route on the rheological behaviour of semi-solid A356 alloy. Techniques used were: electromagnetic stirring (EMS) and chemical ultra-refining (UR). Samples were re-heated to 580°C (∼ 0.45 solid fraction) and hold for 0, 90 and 210s to allow the observation of the structure evolution. After structures characterization, the samples were submitted to compression tests, at δH/δt = 10mm/s, in the same temperature/holding time conditions. Viscosity of the differently prepared raw material was related to the grain size, primary particle size, geometrical factor (roundness shape factor and contiguity).116-117565568Vivés, C., (1992) Light Metals 1992, pp. 1257-1262Flemings, M.C., (1991) Metallurgical Transactions A, 22 A, pp. 957-981Liu, S., Lu, S., Hellawell, A., (1997) Light Metals 1997, pp. 933-936Ito, Y., Flemings, M.C., Comie, J.A., (1992) Proc. of TMS Symposium - Nature and Properties of Semi-Solid Materials, pp. 3-17. , San Diego, USALaxmanan, V., Flemings, M.C., (1980) Metallurgical Transactions, 11 A, pp. 1927-1937Gullo, G., Steinhoff, K., Uggowitzer, P.J., (2000) Proc. of the 6th Int. Conf. on Semi-Solid Proc. of Alloy and Comp, pp. 367-372. , Turin, ItalyGurland, J., (1959) Transactions of AIME, 215, pp. 601-608Zoqui, E.J., Paes, M., Es-Sadiqi, E., (2002) J. of Mat. Proc. Technology, 120, pp. 365-373Zoqui, E.J., Shehata, M.T., Paes, M., Kao, V., Es-Sadiqi, E., (2002) Materials Science & Engineering A, A325, pp. 38-53Paes, M., Zoqui, E.J., (2005) Materials Science & Engineering A, A406, pp. 63-7

Thixoforming Of Aluminium-silicon Alloys In A Mechanical Eccentric Press

The semisolid processing technology is not widely used due to the high cost of raw material and the equipment it requires. New low-cost raw materials and processes could be the key to expand the use of this technology. This paper describes an initial effort to develop new Al-Si-Mg in terms of raw material production and processing. The morphological evolution of all the alloys produced was characterized during their reheating to the semisolid state at 45 and 60% solid fraction, as well as the semisolid behaviour in terms of viscosity versus shear rate. The adaptation of the semisolid technology to the thixoforming process via eccentric press was tested using an equipment up to 25 tons. This type of equipment is not commonly employed in this kind of processing. Results indicate that alloys with low silicon content, e.g., 2 or 4wt%Si, behave similarly to alloys with 7wt%Si, which are normally used in the thixoforming process, with a viscosity of about 2 * 105 Pa.s, The semisolid behaviour of low silicon alloys indicates the potential expansion of the range of raw materials for this application. Thixoforming of semisolid materials in an eccentric press appears to be a very promising technology, yielding parts that, despite their simplicity and restricted shape, display a very good final mechanical behaviour.141-143517522Udvardy, S., (2001) Science and Technology of Semisolid Metal Processing, pp. 6-1. , North American Die Casting AssociationPaes, M., Zoqui, E.J., (2005) Materials Science and Engineering, A406 (1-2), pp. 63-73Young-Dong, K., Zin-Hyoung, L., (2003) Materials Science and Engineering, A360, pp. 372-376S. Nafisi, R., Journal of Materials Science 41 (2006), p. 7954-7963Zhang, B., Cui, J., Lu, G., (2003) Materials Science and Engineering A, 355, pp. 325-330Zoqui, E.J., Gracciolli, J.I., Lourençato, L.A., (2008) Journal of Materials Processing Technology, 198, pp. 155-161Lashkari, O., Ghomashchi, R., (2007) Journal of Materials Processing Technology, 182 (1-3), pp. 229-24

Enhanced refinement and modification via self-inoculation of Si phase in a hypereutectic aluminium alloy

The alloy A390 was ultrasonically treated, and the resulting material was referred to as master alloy. The master alloy was added into a non-treated A390 melt over two different levels: 10 and 20% by volume in order to investigate its potency for silicon refinement. Appropriate refinement of primary silicon crystals is obtained by the addition of master alloy. The addition leads to significant formation of twins and stacking faults where the former produces branching and the latter contributes to growth retard providing ∼10 μm Si primary particles. Minor eutectic Si modification is established by the Si clusters which are provided by the master alloy. By master alloy addition, roundness and aspect ratio of eutectic silicon were enhanced and the tensile properties as well as the wear resistance were improved. The morphological evolution, as well as the mechanisms involved in the primary Si refinement and eutectic modification are defined and discussed252294303CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP306896/2013-3; 190088/2014-12013-09961-3The authors extend their gratitude to the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP; project no. 2013-09961-3), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq; project nos. PQ: 306896/2013-3 and TWAS:190088/2014-1) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for providing financial support. They would like to thank the School of Mechanical Engineering at University of Campinas (UNICAMP) and the Microscope Laboratory of Sao Carlos Universit

Mechanical properties of thixoformed hypoeutectic gray cast iron

The effects of thixoforming process variables on the final mechanical properties of a specially designed hypoeutectic cast iron were studied. An Fe-2.6 wt%C-1.5 wt%Si alloy was prepared using conventional sand casting molds and thixoformed in an eccentric press. Different temperatures and heat-treatment holding times were tested. After being heated to the semisolid state at 1160 °C and 1180 °C and held at these temperatures for 0, 30, 60 and 90 s, the samples were subjected to the thixoforming process. The holding time in the semisolid range simulates the industrial heating process, which is time controlled rather than temperature controlled. The results indicate that the forces applied during thixoforming are closely related to the liquid fraction of the hypoeutectic gray cast iron. A comparative analysis of the behavior of the tensile properties, Vickers microhardness and porosity before and after thixoforming was carried out. The stress-strain curves were similar for the different liquid fractions studied: at 1160 °C the average values were YE = 282 MPa, UTS = 289 MPa, E = 0.21% and Vickers microhardness = 274HV, while at 1180 °C the corresponding figures were YE = 272 MPa, UTS = 277 MPa, E = 0.2% and Vickers microhardness = 257HV. The small variations in tensile properties can be attributed to the final graphite morphology of the thixoformed alloy. The results also show that after thixoforming, the porosity of the Fe-2.6 wt%C-1.5 wt%Si alloy decreased for all experimental conditions and had a maximum value of 5%. There was no significant difference in hardness between the thixoformed material and the as-cast alloy226146156CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES306896/2013-3095/201