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.
KeywordsTitanium Furnace Recrystallization Ductility Tate
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