Methods of Refining Coarse-Grained Structures of Titanium Alloys
The specific features of titanium alloys are their tendency towards grain growth at temperatures ≥ Ttrans. and the resulting drastic deterioration of their mechanical properties and ductility in particular (beta embrittlement). Since the coarse-grained structure of titanium alloys cannot be improved by phase transformation hardening(1), the main method of grain refinement is at present a rather laborious process including sufficient beta deformation and considerable (≥ 50%) alpha+beta deformation. The latter makes it possible to obtain a fine-grained structure of globular or fibrous type and, accordingly, high strength and ductility, but it fails to provide an optimum level of high-temperature strength and fracture toughness which can be attained (with adequate ductility) only in the case of a limited beta-transformed (plate-like alpha) structure (Dgrain = 150 to 200 μm depending upon the alloy and temper.).
KeywordsTitanium Alloy Resistance Heating Beta Phase Alpha Phase Cast Billet
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- 1.Sadovsky, V. D. and Bogachev, Fizika metallov i meyallovedeniye, 1960, v. 10, 132.Google Scholar