Microstructure and Mechanical Properties of an Al-Zn-Mg-Cu Alloy Processed in Semi-Solid State by Means of Twin Screw

مهندسی متالورژی و مواد

Article 1, Volume 31, Issue 1 - Serial Number 21, March 2020, Pages 1-12   

Document Type: Original Articles

DOI: 10.22067/ma.v30i2.53138

Authors

S.Reza Damadi¹; Rasul Azari^{* 1}; Masoud Emami²

¹Sahand university of technology

²university of tehran

Abstract

In this study a super high-strength Al-Zn-Mg-Cu alloy was rheo- extruded by a co-rotating twin-screw extruder with different solid fractions and rotation speeds. Nominal composition of Al-14Zn-9Mg-5.2Cu and process temperature interval was thermodynamically determined. FESEM and optical microscopes were used to investigate micro structural features. Optimized combination of strength and ductility was obtained at 0.6 solid fraction and 450 rpm for screws. The mechanical properties of the rheo- extruded samples at these conditions were: UTS of 682, 621MPa 0.2% proof stress and 10% elongation.

Keywords

Twin-screw extruder; Semi-solid; Thermodynamic; Rheo-extrusion; Super high-strength aluminum alloy

Supplementary Files

1- Damadi- Revised.pdf

References

1. Memongkol, N. and J. Wannasin, "Development of an Aluminum Semi-Solid Extrusion Process". Journal of Metals, Materials and Minerals, Vol.20 No.2 pp. 17-21, )2010(.

2. Alipour, M. and M. Emamy, "Effects of Al -5Ti -1B on the structure and hardness of a super high strength aluminum alloy produced by strain-induced melt activation process". Materials & Design, Vol.32 No8, pp. 4485-4492, (2011).

3. Alipour, M., et al., "Effects of pre-deformation and heat treatment conditions in the SIMA process on properties of an Al-Zn-Mg-Cu alloy modified by Al-8B grain refiner". Materials Science and Engineering: A, Vol. 528, No. 13 pp. 4482-4490, (2011)

4. Fan, Z., Semisolid metal processing. International materials reviews, Vol. 47, No.2, pp. 49-85, (2002).

5. Fan, Z., X. Fang, and S. Ji, "Microstructure and mechanical properties of rheo-diecast (RDC) aluminium alloys". Materials Science and Engineering: A. Vol. 412, No.1, pp. 298-306, (2005).

6. Flemings, M.C., "Behavior of metal alloys in the semisolid state. Metallurgical Transactions B". Vol.22, No.3, pp. 269-293, (1991).

7. Flemings, M.C., R. Mehrabian, and D.B. Spencer, "Composition and methods for preparing liquid-solid alloys for casting and casting methods employing the liquid-solid alloys", Google Patents, (1976).

8. Spencer, D.B., R. Mehrabian, and M.C. Flemings, "Rheological behavior of Sn-15 pct Pb in the crystallization range. Metallurgical Transactions". Vol. 3, No.7, pp. 1925-1932, (1972).

9. Fan, Z., S. Ji, and M. Bevis, "Method and apparatus for making metal alloy castings". Google Patents, (2001).

10. Xia, M., et al., "Continuous twin screw rheo-extrusion of an AZ91D magnesium alloy". Metallurgical and Materials Transactions A, Vol.43, No.11, pp. 4331-4344, (2012).

11. Ji, S., Z. Fan, and M.J. Bevis, "Semi-solid processing of engineering alloys by a twin-screw rheomoulding process". Materials Science and Engineering: A. Vol.299, No.1, pp. 210-217, (2001).

12. Liu, D., H.V. Atkinson, and H. Jones, "Thermodynamic prediction of thixoformability in alloys based on the Al-Si-Cu and Al-Si-Cu-Mg systems". Acta Materialia, Vol.53, No.14, pp. 3807-3819, (2005).

13. Tzimas, E. and A. Zavaliangos, "A comparative characterization of near-equiaxed microstructures as produced by spray casting, magnetohydrodynamic casting and the stress induced", melt activated process. Materials Science and Engineering: A. Vol.289, No.1, pp. 217-227, (2000).

14. Liu, Y.Q. and Z. Fan. "Magnesium alloy selection for semi-solid metal processing". in Proceedings of the 7th International Conference on Semi-Solid Processing of Alloys and Composites, Tsukuba, Japan, S2P, B35, pp. 587-592, (2002).

15. Camacho, A.M., et al., "Thermodynamic predictions of wrought alloy compositions amenable to semi-solid processing". Acta Materialia. Vol.51, No.8, pp. 2319-2330, (2003).

16. Han, Q. and S. Viswanathan, "The use of thermodynamic simulation for the selection of hypoeutectic aluminum-silicon alloys for semi-solid metal processing". Materials Science and Engineering: A. Vol. 364, No.1, pp. 48-54, (2004).

17. Fan, Z., G. Liu, and Y. Wang, "Microstructure and mechanical properties of rheo-diecast AZ91D magnesium alloy". Journal of materials science. Vol.41, No.12, pp. 3631-3644, (2006).

18. Yang, L.-Q., et al., "Microstructure and mechanical properties of rheo-diecasting AZ91D Mg alloy". Transactions of Nonferrous Metals Society of China, Vol. 20, pp. 862-867, (2010).