| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that, though a titanium alloy is used for various plants and apparatuses for conveyance because of its excellent specific strength and corrosion resistance, and further, it is recently used as a biomaterial because of its excellent bio-compatibility, but, the casting of anα+βtype titanium alloy is composed of large crystal grains, and its strength is low, and to improve the superplastic elongation of an alloy rolled-annealed material by using a superplastic working method as a plastic working method for a hardly workable material such as anα+βtype titanium alloy rolling-annealing material. SOLUTION: The titanium alloy is composed in such a manner that a suitable amount of boron is added on the fusion of anα+βtype titanium alloy ingot. Thus, the solidified structure is converted into equiaxed fine grains, so that its mechanical properties (strength) can be improved. Further, as for a countermeasure for improving the superplastic elongation, a suitable amount of boron is added to anα+βtype titanium alloy, and, working and heat treatment are performed. As a result, plastic working for a component with a complicated shape is facilitated by the superplastic working using the above properties, so that the expansion of the application of the titanium alloy can be expected. COPYRIGHT: (C)2005,JPO&NCIPI
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