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THERMOMECHANICAL TREATMENT OF ALUMINIUM ALLOYS.

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The effects of thermomechanical treatment (TMT) on the engineering properties of aluminum alloys are discussed. At present, only one type of TMT seems commercially practicable. This is a T3XX type treatment for 2000 series alloy sheet. Of the other kinds of TMT those with the most potential are high-temperature aging final thermomechanical treatments (FTMT). Factors unfavorable to commercial exploitation of TMT are the extra costs, particularly if hot working is involved, the significant improvements in properties obtainable from conventionally processed newer alloys, the promising results for powder metallurgy alloys, which, however, also entail additional processing costs, and the lack of consistent improvement of fatigue properties by TMT. The main incentive for continued investigation of TMT and the most likely key to its commercial exploitation is the possibility of improving fatigue properties.
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AIAA Paper No. 74-338
  • R W Mcanally
R.W. McAnally, AIAA Paper No. 74-338, AIAA/ASME/SAE 15th Structures, Structural Dynamics and Materials Conference, Las Vegas, April 1974.
  • J T Staley
J.T. Staley, Metals Eng. Quart., 16 No. 2 7 52 (1976). -12-
  • E Di Russo
  • M Conserva
  • M Buratti
  • F Gatto
E. Di Russo, M. Conserva, M. Buratti and F. Gatto, Mater.Sci. Eng., 14,23 (1974).
  • Di Russo
  • M Buratti
E. Di Russo and M. Buratti, I.S.M.L. Report N 75/23 649, June 1975.
  • J Waldman
  • H Sulinski
  • H Markus
J. Waldman, H. Sulinski and H. Markus, Met.Trans., 5, 573 (1974).
  • S Pattanaik
  • V Srinivasan
  • M L Bhatia
S. Pattanaik, V. Srinivasan and M.L. Bhatia, Scripta Met., 6, 191 (1972).
  • H Martinod
  • C Renon
  • J Calvet
H. Martinod, C. Renon and J. Calvet, O.N.E.R.A. TP 423 (1966).
  • D S Thompson
  • S A Levy
  • G E Spangler
D.S. Thompson, S.A. Levy and G.E. Spangler, Aluminium, 50, 647 (1974).
  • M Buratti
  • M Conserva
  • E Di Russo
M. Buratti, M. Conserva and E. Di Russo, Alluminio, 43, 108 (197 4).
  • M Conserva
  • M Leoni
M. Conserva and M. Leoni, Met.Trans., 6A, 189 (1975).