Rheological behavior of semi-solid AZ91D magnesium alloy at steady state

Abstract

The rheological behavior of semi-solid AZ91D magnesium alloy was investigated in isothermal steady state condition. The effects of stirring temperature and shearing rate on apparent viscosity of semi-solid alloy slurry at steady state were discussed. The results show that the apparent viscosity of semisolid AZ91D alloy increases with increasing solid fraction. It increases slightly before the solid fraction reaches a certain value, about 0.4, and then goes up rapidly after the solid fraction reaches the critical value. However, the apparent viscosity decreases with increasing shearing rate, and the reduction amplitude is higher when the solid fraction is higher. According to the experimental data, an empirical equation that shows the effect of solid fraction and shearing rate on the apparent viscosity of semi-solid AZ91D alloy can be built as η _a=9.7×10⁻²exp(13.87f _s)γ^−0.58.

Keywords

semi-solid magnesium alloy / apparent viscosity / solid fraction / shearing rate

References

[1] Flemings M C Behavior of Metal Alloys in the Semisolid State[J]. Metallurgical Transaction A, 1991, 22(5): 957-981.

[2] Fan Z Semisolid Metal Processing[J]. International Materials Reviews, 2002, 47(2): 49-85.

[3] Luo S J, Tian W T, Xie S S, . Technology and Applications of Semi-solid Forming [J]. The Chinese Journal of Nonferrous Metals, 2000, 10(6): 765-773.

[4] Luo S J, Chen Y S, Shan W W The Rheology of Semi-solid Metal[M], 2011 Beijing: National Defence Industry Press

[5] Joly P A, Mehrabian R The Rheology of a Partially Solid Alloy [J]. Journal of Materials Science, 1976, 11: 1 393-1 418.

[6] Atkinson H V Modeling the Semisolid Processing of Metallic Alloys [J]. Progress in Materials Science, 2005, 50: 341-412.

[7] Zhou Z H, Mao W M, Liu Z, . Rheological Behavior of Semisolid AlSi6Mg2 Aluminium Alloy at Steady State [J]. ACTA METALLURGICA, 2005, 41(7): 759-762.

[8] Terzieff P A Pseudopotential Approach to the Viscosity of Liquid Cubased Alloys [J]. Journal of Alloys and Compounds, 2009, 473: 195-200.

[9] Gautham B P, Kapur P C Rheological Model for Short Duration Response of Semi-solid Metals [J]. Materials Science and Engineering A, 2005, 393: 223-228.

[10] Hu Y, He B L, Yan H Rheological Behavior of Semi-solid Mg2Si/AM60 Magnesium Matrix Composites at Steady State[J]. Transactions of Nonferrous Metals Society of China, 2010, 20: 883-887.

[11] Li D N, Luo J R, Wu S S, . Study on the Semi-solid Rheocasting of Magnesium Alloy by Mechanical Stirring[J]. Journal of Materials Processing Technology, 2002, 129: 431-434.

[12] Yim C D, Shin K S Semi-solid Processing of Magnesium Alloys [J]. Materials Transactions, 2003, 44(4): 558-561.

[13] Sannes S, Gjestland H, Arnberg L, . Yield Point Behavior of Semisolid Mg Alloys [J]. Proc. 3rd Int. Conf. Semi-Solid Processing of Alloys and Composites, 1994 271-280.

[14] Jiang Y X, Xie S S, Yang H Q, . Influence of Procedure Parameters on Rheological Property of Semi-solid AZ91D Magnesium Alloy [J]. The Chinese Journal of Nonferrous Metals, 2005, 15(2): 35-385.

[15] Hu Y, Yan H, Wu X Q Research of Rheo Model of Semi-solid Mg2Si/AM60 Magnesium Matrix Composites [C]. 2010 International Conference on Mechanic Automation and Control Engineering, Wuhan, China, 2010 5 777-5 780.