Effect of Cold Work on the Precipitation Process in Aluminum Alloy 6063

Sherko Shakir Fettah1, Omer Salih Mahmood1, & Shawnim R. Jalal Rojbeyani2

1 College of Engineering, University of Sulaimani, 2 College of Engineering, Salahaddin University

DOI: https://doi.org/10.17656/jzs.10146

Abstract

Aluminum alloys can be strengthened by cold or hot working due to interaction between precipitates and dislocations. The alloy 6063 was deformed (2, 5, 10, 15 and 20) % after water quenching, and artificially aged at different aging temperatures (1605 180 and 200) oc for various periods of time (0.5, 5, 10, 50 and 100) hours. The results showed a considerable improvement in yield and tensile strength with an increasing level of prestrain. Generally aging temperature of 160 oc gave the best increase of yield and tensile strength, but these were decreased with increasing aging temperature i.e. (180 and 200) oc at a given level of prestrain.

The peak aging time that improves the mechanical properties decreased with an increasing aging temperature. The alloy of 20 % deformation and aged at 160 oc for 10 hours developed maximum (yield, tensile strength and hardness) values compared with all other conditions involved, because the density of dislocation tangles which improved (yield and tensile) strength increased with increasing degree of prestrain.

The 6xxx aluminum alloys are readily welded by most types of welding processes, but with severe local softening in the heat-affected zone (HAZ) where the hardness reduces to about half that of the parent metal.

Keywords:- cold work, precipitation, heat-treatment, microstructure, aluminum alloy 6063, mechanical properties.

References

1- Dwight, JEB "Aluminum Design and Construction" E&FN Spon, 1999. 1-14& 46100.

2- Hedly, sew, Das, S. and Miller, JAM "Aluminum Automotive uses" The department of energy's role, March 2000, 1-20

3- Cobden, R. Alcan and Banbury "Aluminum: physical properties characteristics and alloys" TALAT Lecture 1501, EAA, 1994, 8-29.

4- Dorward, R.C and Bouvier, C. "A rationalization of factors affecting strength, ductility and toughness of 6061 type Al-Mg-Si (Cu) alloys" Material Science and Engineering, A 254 

5- The Aluminum Association, Inc "Aluminum alloy Selection and Applications" Washington, DC. December 1998, 11-13.

6- Polwer, I.J "Light alloys Metalluro of the light metals" Edward Arnold. 1989, pp 20-141

7- Missori, S. and Sili, A. "Mechanical behaviors of 6082-T6 aluminum alloy weld' Metallurgical Science and Technology, 18,.1, 13, 2000.

8- Automotive and Light Truck Group Sponsors "Aluminum: The corrosion Resistant Automotive Materials" AT7-May 2001, The Aluminum Association, Inc.. 2-6.

9- Quainoo, G.K, Yannacopoulos, S. and Gupta A.K. "Strengthening characteristics of Aluminum Alloys 6111" Canadian Metallurgical Quarterly, 2001, 40, 2,. 211-220.

10- Miao, W-F and Laughlin, DE. "Precipitation hardening in Aluminum Alloys 6022" Acta Metallurgical Inc. Script Materialia,. 1999, 40. 7,. 873-878.

11- Murayma, M. and Hono, K. "Pre-Precipitate clusters andprecipitation processes in Al-Mg-Si alloys" Acta Mater, 1999,47, 5, 1537-1548

12- Deschamps, A., Brechet, Y. and Guyot, P. "Interactions between plasticity and precipitation" 7th Seminar of the International Federation for Heat-treatments and surface engineering, Budapest, Hungary, 1999.,1-9.

13- Hand book "Mechanical Engineers" 2nd, John Wiley & Sons. Inc. 1998, pp. 45-57.

14- Higgins, R.A "Engineering Metallurgy, Applied Physical Metallurgy" Sixth Edition, Edward Arnold, 1998. 175-178, 206-213, 206428,

15- Jacobs, M. H "Precipitation Hardening" TALA T Lecture/204, EAA, 1999, 3-20.

16- Cullister, William D.Jr. "Materials Science and Engineering an Introduction" John Wily & sons, Inc, 1997,. 363-364.

17- Henkel, Daniel P. and Pense, Alan W. "Structure and Properties of Engineering Materials" Mc Graw-Hill 2002, 86-108.

18- Cerri, E. and Evangelista, E. "Metallography ofAluminum alloys" EAA, 1999,3

 Eskin, Dmitry G. and Kharakterova, Marina L. "The effect ofSilicon and Copper on the precipitation hardening of sheets of aluminum 6000 series alloys" Mater. Tehnol, 2001. 5-8.

20- Rack, H. J "The Influence of strain upon precipitation in a light-purity 6061 AA" Material Science and Engineering, 29, 1977. 179-188.

21- Bergsma, S.C, Kassner, M.E, Li X. and Wall M.A. "Strengthening in the new aluminum alloy  Science and Engineering A 254, 1998,.112-118.

View Full Article