TITANIUM ALLOY HAVING HIGH STRENGTH, HIGH YOUNG'S MODULUS, EXCELLENT FATIGUE PROPERTIES, AND EXCELLENT IMPACT TOUGHNESS

摘要

Provided is an α+β titanium alloy hot-rolled sheet consisting of, in mass %, Al: 4.7 to 5.5%, Fe: 0.5 to 1.4%, N: less than or equal to 0.03%, Si: 0.15 to 0.40%, a ratio of Si/O: 0.80 to 2.80, [O]_eq in Expression (1): more than or equal to 0.13% and less than 0.25%, and the balance: Ti and impurities. In a case where an ND direction represents a normal direction of the hot-rolled sheet, a TD direction represents a sheet-width direction of the hot-rolled sheet, a c-axis orientation represents a normal direction of a (0001) plane in an α phase, XND represents a strongest intensity among X-ray (0002) reflection relative intensities of crystal grains in which the c-axis orientation is in a range of 30° from the ND direction, and XTD represents a strongest intensity among intensities in which the c-axis orientation is in a range of ±10 degrees in the TD direction, XTD/XND is more than or equal to 4.0, a Young's modulus in the sheet-width direction is more than or equal to 135 GPa, and tensile strength in the sheet-width direction is more than or equal to 1100 MPa,; [O]_eq=[O]+2.77[N]  Expression (1).