Heat treatment for improved properties of alpha-beta titanium-base alloys

A method for heat treating a material, comprising the steps of:

• furnishing an alpha-beta titanium-base alloy capable of forming mixtures of alpha and beta phases and having a beta transus between an alpha-plus-beta phase field and a beta phase field of a temperature-composition equilibrium phase diagram of the furnished alpha-beta titanium-base alloy;
• thereafter
• first heating the alpha-beta titanium-base alloy to a first heat-treatment temperature in a first range of from about 70° F. below a beta transus temperature of the alpha-beta titanium-base alloy to the beta transus temperature of the alpha-beta titanium-base alloy;
• thereafter
• quenching the alpha-beta titanium-base alloy at a rate of greater than about 200° F. per minute;
• thereafter
• second heating the alpha-beta titanium-base alloy to a second heat-treatment temperature in a second range of from about 100° F. to about 400° F. below the beta transus temperature of the alpha-beta titanium-base alloy;
• and thereafter
• cooling the alpha-beta titanium-base alloy to ambient temperature at a rate of from about 10° F. per minute to about 200° F. per minute.

A method for heat treating a material, comprising the steps of:

• furnishing an alpha-beta titanium-base alloy capable of forming mixtures of alpha and beta phases and having a beta transus between an alpha-plus-beta phase field and a beta phase field of a temperature-composition equilibrium phase diagram of the alpha-beta titanium-base alloy;
• thereafter
• first heating the alpha-beta titanium-base alloy to a first heat-treatment temperature within the alpha-plus-beta phase field, the step of first heating producing a volume fraction of primary alpha phase of less than about 30 percent within a primary beta phase matrix;
• thereafter
• quenching the alpha-beta titanium-base alloy at a rate sufficient to suppress the epitaxial regrowth of the primary alpha phase and to produce a transformed beta morphology in the beta phase;
• thereafter
• second heating the alpha-beta titanium-base alloy to a second heat-treatment temperature less than a growth temperature at which a primary alpha phase level is substantially affected by epitaxial growth and greater than an ordering temperature at which an ordering reaction occurs;
• and thereafter
• cooling the alpha-beta titanium-base alloy at a rate sufficient to avoid ordering reactions in the alpha-beta titanium-base alloy, the microstructure resulting after the step of cooling having less than about 30 percent by volume of primary alpha phase dispersed within a transformed and coarsened matrix phase selected from the group consisting of transformed and coarsened Widmanstatten phase and martensitic beta phase.

A method for heat treating a material, comprising the steps of:

• furnishing an alpha-beta titanium-base alloy capable of forming mixtures of alpha and beta phases and having a beta transus between an alpha-plus-beta phase field and a beta phase field of a temperature-composition equilibrium phase diagram of the alpha-beta titanium-base alloy;
• thereafter
• first heating the alpha-beta titanium-base alloy to a first heat-treatment temperature in a first range of from about 70° F. below a beta transus temperature of the alpha-beta titanium-base alloy to the beta transus temperature of the alpha-beta titanium-base alloy;
• thereafter
• quenching the alpha-beta titanium-base alloy at a rate of greater than about 200° F. per minute;
• thereafter
• second heating the alpha-beta titanium-base alloy to a second heat-treatment temperature in a second range of from about 100° F. to about 400° F. below the beta transus temperature of the alpha-beta titanium-base alloy;
• and thereafter
• cooling the alpha-beta titanium-base alloy to ambient temperature at a rate of from about 10° F. per minute to about 200° F. per minute, the microstructure resulting after the step of cooling having less than about 30 percent by volume of primary alpha phase dispersed within a transformed and coarsened matrix phase selected from the group consisting of transformed and coarsened Widmanstatten phase and martensitic beta phase.