Processing of a High-Strength, Heavy Section Titanium Alloy by Extrusion Methods
Utilization of advanced Ti alloys in heavy sections depends to a large extent on the ability to fabricate these sections. This study is concerned with the high-strength, metastable beta alloy Ti-8 Mo-8 V-2 Fe-3 Al (Ti-8823) and its fabrication into large sections. The extrusion technique utilized to achieve better than a 6:1 reduction ratio for fabrication of a thick wall cylinder of this alloy is described. Following extrusion, the alloy is given one of two heat treatments; the commonly suggested solution treatment and age (STA), or a direct age without the intermediate solutionizing. The influence of this heat treatment is given in terms of microstructure and mechanical properties. It is shown that direct aging of the Ti-8823 alloy after extrusion offers significant improvements in mechanical properties over the STA practice. Not only are the mechanical properties uniform through the section as a result of direct aging but they are generally superior to those of the STA material.
KeywordsFracture Toughness Titanium Alloy Direct Aging Extrusion Method Heavy Section
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- 1.Hunter, D.B., “Metastable Beta Sheet Alloy Ti-8 Mo-8 V-2 Fe-3 Al”, Watertown Arsenal, Mass., Report No. WAL-TR-405/2-14, October 1966. (AD 648 244)Google Scholar
- 2.Heil, W.H., “New Developments in High Strength Titanium Alloys”, paper presented at Titanium Course, New York University, Sept. 1969.Google Scholar
- 3.Chait, R. and DeSisto, T.S., “The Fracture Toughness of Three Heavy Section Titanium Alloys”, Army Materials and Mechanics Research Center, Watertown, Mass., Report No. AMMRC PTR-72-5, October 1972. (AD 753 919)Google Scholar
- 4.Bohanek, E., “Evaluation of Several Commercial Heats of Ti-8 Mo-8 V-2 Fe-3 Al”, Titanium Metals Corporation of America, West Caldwell, N.J., Mechanical Report No. 45, August 1970.Google Scholar
- 5.Bohanek, E., “Extrusion and Processing of Ti-3 Al-2.5 V and Ti-8 Mo-8 V-2 Fe-3 Al Tube Hollows”, Titanium Metals Corporation of America, West Caldwell, N.J., Technical Report No. 18, February 1972.Google Scholar
- 6.Altan, T., Gerds, A.F., Nichols, D.E., Henning, H.J. and Fiorentino, R.J., “A Study of Mechanics of Closed-Die Forging”, Army Materials and Mechanics Research Center, Watertown, Mass., Contract Report No. AMMRC CR-70-18, August 1970. (AD 711 544)Google Scholar
- 7.“Plane-Strain Fracture Toughness of Metallic Materials”, Standard Test Method E399-72, in Annual Book of ASTM Standards, Part 31, Philadelphia: American Society for Testing and Materials (1973), 960–79.Google Scholar
- 8.Rollins, K.A., Chait, R. and Lum, P.T., “On the Precracking Procedures for Fracture Toughness Determination”, Army Materials and Mechanics Research Center, Watertown, Mass., Technical Note No. AMMRC TN-72-24, September 1972.Google Scholar
- 9.Adair, A.M. and Roberson, J.A., “The Influence of Thermomechanical Processing on the Structure and Properties of Extruded Beta III Titanium”, in Proceedings of the Second International Conference on the Strength of Metals and Alloys, Vol. III. Metals Park, Ohio: American Society for Metals (1970), 932–36.Google Scholar