Titanium alloys and method for manufacturing titanium alloy materials

Abstract

A cold rolled titanium alloy plate with a sufficient cold workability and excellent superplasticity characteristics is provided. The cold rolled titanium alloy plate consists of, by mass %, Al of 2.0 to 4.0% and V of 4.0 to 9.0%, one element selected from Zr of not more than 2.0% and Sn of not more than 3.0% and the balance being Ti and impurities, a ratio of α/β is not less than 0.3 and not more than 0.6; where “α” is an area of a phase in the plate and “β” is an area of β phase in the plate, and the plate has an elongation at break in a tensile test conducted at 800° C. exceeds 200%.

1 . A cold rolled titanium alloy plate consisting of, by mass %, Al of 2.0 to 4.0% and V of 4.0 to 9.0%, one element selected from Zr of not more than 2.0% and Sn of not more than 3.0% and the balance being Ti and impurities,
 wherein a ratio of α/β is not less than 0.3 and not more than 0.6; where “α” is an area of a phase in the plate and “β” is an area of β phase in the plate, and   wherein the plate has an elongation at break in a tensile test conducted at 800° C. exceeds 200%.   
     
     
         2 . A cold rolled titanium alloy plate consisting of, by mass %, Al of 2.0 to 4.0% and V of 4.0 to 9.0%, one element selected from Zr of not more than 2.0% and Sn of not more than 3.0%, further one or more elements selected from Fe of not less than 0.20% and not more than 0.95%, Cr of not less than 0.01% and not more than 0.95%, Cu of 0.01 to 1.0% and Ni of 0.01 to 1.0%, and the balance being Ti and impurities,
 wherein a ratio of α/β is not less than 0.3 and not more than 0.6; where “α” is an area of a phase in the plate and “β” is an area of 13 phase in the plate,   wherein the plate has an elongation at break in a tensile test conducted at 800° C. exceeds 200%, and   wherein Veq obtained by the following equation (1) is in a range of 4.0 to 9.5:
     Veq=V+ 1.9Cr+3.75Fe  (1)
 
   where a symbol of element on a right side of the equation (1) means a content of the element by mass %.   
     
     
         3 . A method for manufacturing the titanium alloy material consisting of, by mass %, Al of 2.0 to 4.0%, V of 4.0 to 9.0%, Zr of 0 to 2.0%, Sn of 0 to 3.0%, further one or more elements selected from Fe of 0.20 to 1.0%, Cr of 0.01 to 1.0%, Cu of 0.01 to 1.0% and Ni of 0.01 to 1.0%, and the balance being Ti and impurities, wherein the titanium alloy with the Veq obtained by the following equation (1) being in the range of 4.0 to 9.5 is subjected to the cold working at the cross-section reduction rate of 40% or more:
     Veq=V+ 1.9Cr+3.75Fe  (1)
   where a symbol of element on the right side of the equation (1) means a content of the element by mass %.