Method of Making High Strength-High Stiffness Beta Titanium Alloy

1 . A method of making a high strength, high stiffness beta titanium alloy, comprising:

introducing boron into a beta titanium alloy to produce TiB precipitates;

heat treating the titanium alloy with TiB precipitates by homogenization above the beta transus temperature of the alloy;

subjecting the heat treated alloy to a hot metalworking operation below the beta transus temperature;

heat treating the worked alloy with a solution treatment below the beta transus temperature; and

ageing the solution treated alloy below the beta transus temperature.

2 . The method of claim 1 wherein the TiB precipitates are produced in the alloy by casting, cast-and-wrought processing, powder metallurgy techniques, e.g., gas atomization, or blended elemental approach.

3 . The method of claim 2 wherein the boron is added to a molten titanium alloy and the liquid melt is atomized to obtain titanium alloy powder containing TiB precipitates, and the titanium alloy powder is consolidated to obtain a fully dense powder compact.

4 . The method of claim 3 wherein the titanium alloy powder is consolidated by hot isostatic pressing.

5 . The method of claim 1 wherein the beta transus temperature of the alloy is about 1580° F. and the alloy is heat treated by homogenization at a temperature range of about 1900-2200° F. for 2-4 hours.

6 . The method of claim 5 wherein the hot metalworking is forging, rolling or extrusion at a temperature of about 1500° F.

7 . The method of claim 6 wherein the heat treated alloy is extruded at a ram speed of approximately 120 inch/min.

8 . The method of claim 7 wherein the heat treated alloy is extruded from a powder compact into a bar.

9 . The method of claim 5 wherein the worked alloy is heat treated with a solution treatment at approximately 1500° F. for about 1 hour and cooled to room temperature.

10 . The method of claim 9 wherein the heat treated and worked alloy is gas furnace cooled to room temperature at a cooling rate of about 200° F./minute.

11 . The method of claim 9 wherein the solution treated alloy is aged at about 1100° F. for about 6 hours.

12 . The method of claim 11 wherein the aged alloy is air cooled to room temperature.

13 . The method of claim 1 wherein the heat treating of the titanium alloy by homogenization improves the tensile elongation while maintaining the tensile strength of the titanium alloy.

14 . The method of claim 1 wherein the ageing of the solution treated alloy increases the tensile strength and tensile modulus of the alloy without a reduction in tensile elongation.

15 . The method of claim 1 wherein the titanium alloy is Ti-5553.

16 . The method of claim 5 wherein the titanium alloy is Ti-5553.