Design of multistep aging treatments of 2099 (C458) Al-Li alloy
- 254 Downloads
Multistep artificial aging treatments coupled with various natural aging times for aluminum lithium 2099 alloy (previously called C458) are discussed to obtain mechanical tensile properties in the T6 condition that match those in the T861 condition, having a yield strength in the range of 414–490 MPa (60–71 ksi), an ultimate strength in the range of 496–538 MPa (72–78 ksi), and 10–13% elongation. Yield and ultimate tensile strengths from 90–100% of the strength of the as-received material (in the T861 condition) were obtained. The highest tensile strengths were consistently obtained with two-step, low-to-high temperature artificial aging treatments consisting of a first step at 120 °C (248 °F) for 12–24 h followed by a second step between 165 and 180 °C (329–356 °F) for 48–100 h. These T6-type heat treatments produced average yield and ultimate strengths in the longitudinal direction in the range of 428–472 MPa (62.1–68.5 ksi) and 487–523 MPa (70.6–75.9 ksi), respectively, as well as lower yield strength anisotropy when compared with the as-received material in the T861 condition.
Keywordsaluminum-lithium (Al-Li) anisotropy artificial aging natural aging
Unable to display preview. Download preview PDF.
- 1.R.G. Buchheit, D. Mathur, and P.I. Gouma, Grain Boundary Corrosion and Stress Corrosion Cracking Studies of Al-Li-Cu Alloy AF/C458, Ohio State University, Columbus, OH, undatedGoogle Scholar
- 3.R.J. Rioja, C.J. Warren, M.D. Goodyear, M. Kulak, and G.H. Bray, Al-Li Alloys for Lower Wings and Horizontal Stabilizer Applications, Mater. Sci. Forum, Vol 242, 1997, p 255–260Google Scholar
- 4.B.M. Gable, A.A. Csontos, and E.A. Starke, The Role of Mechanical Stretch on Processing-Microstructure-Property Relationships of AF/C 458, Mater. Sci. Forum, Vol 331–337, 2000, p 1341–1346Google Scholar
- 5.R.J. Rioja, E.L. Colvin, A.K. Vasudevan, and B.A. Cheney, Aluminum Alloy Two-Step Aging Method and Article, U.S. Patent No. 4 861 391, 1989Google Scholar
- 6.G.B. Venema and R.J. Rioja, The Manufacture of C458 Plate at Davenport Works and Lot Release Properties, Proceedings from the Aluminum-Lithium Workshop, ALCOA and Air Force Research Laboratory (AFRL), Wright-Patterson AFB, Bass Lake Lodge, OH, 1998.Google Scholar
- 8.E. Acosta, A. Dakessian, E. Monge, and C. Parrish, Design Process of C458 Aluminum Lithium Alloy, Loyola Marymount University, Los Angeles, CA, 2000Google Scholar
- 9.M. Romios, R. Suchit, R. Nahman, and C. Jones, Heat Treatment Design Process for C458 Aluminum Lithium Alloy, Loyola Marymount University, Los Angeles, CA, 2000Google Scholar
- 10.R. Tiraschi, F. Gaxiola, K. Heung, H. Nassar, H. Babel, C. Parrish, J. Foyos, J. Ogren, and O.S. Es-Said, On Optimizing the Mechanical Strength of C458 Al Alloy for Cryogenic Tank Applications by Various Heat Treatments, Loyola Marymount University, Los Angeles, CA, 2003.Google Scholar
- 11.N. Abourialy, K. Trechter, and G. Wallace, Experimental Design of a Heat Treatment Process for C458-T6 Aluminum-Lithium Alloy, Loyola Marymount University, Los Angeles, CA, 2000Google Scholar
- 12.R.J. Rioja and R.S. James, Heat Treatments of Aluminum-Lithium Alloys, U.S. Patent No. 5 076 859, 1991Google Scholar