| 摘要 |
PURPOSE: To impart excellent mechanical strength, particularly, excellent fatigue strength and fatigue crack propagating resist properties to an alloy material and to apply it to the rotating structure of a jet engine by specifying the compsn. of a Ti alloy and forming its metallic structure into an equiaxialαone. CONSTITUTION: This alloy material has a compsn. contg., by weight, 4.5 to 5.5% Al, 1.5 to 2.5% Sn, 3.5 to 4.5% Zr, 2.5 to 3.5% Cr, 2.5 to 3.5% Mo, and the balance Ti with inevitable impurities and has a metallic structure of an equiaxialαone. The content of Cr in the compsn. is preferably regulated to 2.6 to 3.4%. The formation of the metallic structure into the equiaxialαone can be attained by sufficiently executing hot finish working, e.g. forge-expanding at theβtransformation point or below and thereafter subjecting the same to heat treatment at theβtransformation point or below. Ordinary, this heat treatment is constituted of solution treatment and aging treatment.
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