| CPC C22C 14/00 (2013.01) [C22F 1/183 (2013.01); F16B 31/06 (2013.01)] | 19 Claims |
|
1. A meta-stable β titanium alloy comprising
7.5 to 8.5 wt. % vanadium,
5.5 to 6.5 wt. % chromium,
3.5 to 4.5 wt. % molybdenum,
3.5 to 4.5 wt. % zirconium,
3 to 4 wt. % aluminum,
up to 0.30 wt. % oxygen,
a maximum of 0.3 wt. % iron,
nitrogen up to 0.03 wt. %,
hydrogen up to 0.03 wt. %,
a maximum of 50 ppm yttrium,
a maximum of other elements comprising unavoidable impurities present at 0.15 wt. % each and 0.40 wt. % in aggregate,
with a balance (apart from carbon) of titanium;
the alloy having carbon present at a stable total carbon level sufficiently in excess of 0.05 wt. % achieving an improvement in the mechanical properties of ultimate tensile strength (UTS), double shear strength (DSS) and fatigue strength in threaded regions relative to standard Beta-C alloy with a specified carbon level below 0.05 wt. %, with a maximum stable total carbon content of 0.2 wt. %, the stable carbon comprising carbon in solid solution and thereby controlled so as to preclude carbide formation having a detrimental effect on the level of fatigue strength,
wherein, when drawn as a 10 mm to 20 mm rod, the titanium alloy exhibits one or more of: a UTS of about 1500 MPa or more, an elongation of about 9% or more, or a DSS of about 824 MPa or more.
|