Microstructure and Property of Rheo-Diecasting Magnesium-Alloy with Forced Convection Mixing Process

Abstract:

Taking AZ91D magnesium alloy as experimental material, the rheo-diecasting process was implemented by combining the self-developed forced convection rheomoulding device with high pressure die casting machine. Microstructural characteristics of the RDC tensile samples were discussed. Microstructure of semisolid slurry at different rotational speed prepared by FCR device was investigated. Tensile properties and fracture morphology of rheo-diecasting process in different conditions were studied as well. The results indicate that the excellent semisolid microstructure of AZ91D tensile samples can be obtained by forced convection rheo-diecasting process. With the increase of rotational speed, the mean size of the primary particles diminishes and the shape factor increases. The tensile properties of as-cast RDC samples are obviously better than conventional diecasting samples. T6 heat treatment can increase tensile strength and elongation of RDC tensile samples to 286MPa and 6.1%, respectively. The yield strength and elongation of T4 heat treated RDC samples are 100MPa and 12.6%.

• Periodical: Solid State Phenomena (Volumes 217-218)
• Pages: 455-460
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.217-218.455
• Online since: September 2014
• Authors: Bing Zhou, Yong Lin Kang*, Ming Fan Qi, Huan Huan Zhang, Guo Ming Zhu
• Keywords: Heat Treatment, Microstructure, Property, Rheo-Diecasting, Semi-Solid Slurry Preparation

References

[1] H. Friedrich, S. Schumann, Research for a new age of magnesium in the automotive industry, J. Mater. Process. Tech. 117 (2001) 276-281.

[2] I.J. Polmear, Magnesium alloys and applications, Mater. Sci. and Tech. 10 (1994) 1-16.

[3] A. Balasundaram, A.M. Gokhale, Digital image analysis technique for characterization of shrinkage and gas porosity in cast magnesium alloys, in: J. Hryn (Eds. ), Magnesium technology, TMS Annual Meeting, 2001, pp.155-159.

DOI: 10.1002/9781118805497.ch28

[4] Z. Fan, S. Ji, G. Liu. Development of the rheo-diecasting process for Mg-alloys, Mater. Sci. Form. 488-489 (2005) 405-412.

DOI: 10.4028/www.scientific.net/msf.488-489.405

[5] F. Zhang, N.N. Song, J. Zhang, Y.L. Kang and Q. Zhu, Numerical simulation on the filling process of rheological die casting and forming defects analysis, Solid State Phenomena. 192-193 (2013) 293-298.

DOI: 10.4028/www.scientific.net/ssp.192-193.293

[6] L.Q. Yang, Y.L. Kang, F. Zhang, R.H. Ding and J. Li, Rheo-diecasting of AZ91D magnesium alloy by taper barrel rheomoulding process, Trans. Nonferrous Met. Soc. China. 20 (2010) 966-972.

DOI: 10.1016/s1003-6326(09)60243-0

[7] Y. Wang, G. Liu, Z. Fan, Microstructural evolution of rheo-diecast AZ91D magnesium alloy during heat treatment, Acta Materialia. 54 (2006) 689-699.

DOI: 10.1016/j.actamat.2005.09.033

[8] S. Ji, Z. Fan, M.J. Bevis, Semi-solid processing of engineering alloys by a twin-screw rheomoulding process, Mater. Sci. Eng. A. 299 (2001) 210-217.

DOI: 10.1016/s0921-5093(00)01373-3

[9] P.K. Seo, S.M. Lee, C.G. Kang, A new process proposal for continuous fabrication of rheological material by rotational barrel with stirring screw and its microstructural evaluation, J. Mater. Process. Tech. 209 (2009) 171-180.

DOI: 10.1016/j.jmatprotec.2008.01.037

[10] F. Zhang, Y.L. Kang, L.Q. Yang, R.H. Ding, Taper barrel rheomouldiing process for semisolid slurry preparation and microstructure evolution of A356 aluminum alloy, Trans. Nonferrous Met. Soc. China, 20 (2010) 1677-1684.

DOI: 10.1016/s1003-6326(09)60357-5

[11] B. Zhou, Y.L. Kang, J. Zhang, J.Z. Gao, F. Zhang, Forced convection rheomoulding process for semisolid slurry preparation and microstructure evolution of 7075 aluminum alloy, Solid State Phenomena. 192-193 (2013) 422-427.

DOI: 10.4028/www.scientific.net/ssp.192-193.422

[12] C.P. Chen, C. -Y.A. Tsao. Semisolid deformation of non-dendritic structures-I. Phenomenological Behavior, Acta mater. 45 (1997) 1955-(1968).

DOI: 10.1016/s1359-6454(96)00312-6

[13] B. Zhou, Y.L. Kang, G.M. Zhu, J.Z. Gao, M.F. Qi, Forced convection rheoforming process for semisolid slurry preparation and numerical simulation of 7075 alloy, Trans. Nonferrous Met. Soc. China. Accepted for publication (2013).

DOI: 10.1016/s1003-6326(14)63169-1

[14] U.A. Curle, J.D. Wilkins, G. Govender. R-HPDC of Magnesium alloys, Solid State Phenomena. 192-193 (2013) 225-230.

DOI: 10.4028/www.scientific.net/ssp.192-193.225

[15] Z. Fan, Development of the rheo-diecasting process for magnesium alloys, Mater. Sci. Eng. A. 413-414 (2005) 72–78.

DOI: 10.1016/j.msea.2005.09.038

[16] L.Q. Yang, Y.L. Kang, F. Zhang, J. Xu. Microstructure and mechanical properties of rheo-diecasting AZ91D Mg alloy, Trans. Nonferrous Met. Soc. China. 20 (2010) s862-s867.

DOI: 10.1016/s1003-6326(10)60596-1