Method to produce gamma titanium aluminide articles having improved properties

A process for producing duplex microstructure in an article of gamma titanium aluminide alloy containing 0.05 to 1.0 atomic percent boron, which comprises the steps of:

• (a) hot working the article;
• (b) annealing the hot worked article at an annealing temperature in the range of Te+100° C. to Tα−25° C. for about 10 minutes to 15 hours;
• (c) cooling said article from said annealing temperature to an aging temperature in the range of 700° to 1050° C. at a cooling rate of about 5° to 1000° C./min;
• and
• (d) aging the so cooled article at said aging temperature for about 1 to 150 hours.

A process for producing nearly-lamellar microstructure in an article of gamma titanium aluminide alloy containing 0.05 to 1.0 atomic percent boron, which comprises the steps of:

• (a) hot working the article;
• (b) annealing the hot worked article at an annealing temperature in the range of Tα−1° C. to Tα−25° C. for about 0.5 to 10 hours;
• (c) cooling said article from said annealing temperature to a preselected temperature between said annealing temperature and about 700° C. at a first cooling rate of about 5° to 1000° C./min and then cooled at a second rate ranging from said first cooling rate to water quenching to room temperature;
• and
• (d) aging the so cooled article at an aging temperature in the range of 700° to 1050° C. for about 1 to 150 hours.

A process for producing nearly-lamellar microstructure in an article of gamma titanium aluminide alloy containing 0.05 to 1.0 atomic percent boron, which comprises the steps of:

• (a) hot working the article;
• (b) annealing the hot worked article at an annealing temperature in the range of Tα−1° C. to Tα−25° C. for about 0.5 to 10 hours;
• (c) cooling said article from said annealing temperature to an aging temperature in the range of 700° to 1050° C. at a cooling rate of about 5° to 1000° C./min;
• and
• (d) aging the so cooled article at said aging temperature for about 1 to 150 hours.

A process for producing fully TMT lamellar microstructure in an article of gamma titanium aluminide alloy containing 0.05 to 1.0 atomic percent boron, which comprises the steps of:

• (a) hot working the article;
• (b) pre-annealing the hot worked article at a temperature in the range of Tα−12 C. to Tα−100° C. for about 1 minute to 2 hours;
• (c) heating the pre-annealed article to annealing temperature at a rate greater then 20° C./min;
• (d) annealing the hot worked article at an annealing temperature in the range of Tα to Tα+60° C. for about 1 minute to 10 hours;
• (e) cooling said article from said annealing temperature to a preselected temperature between said annealing temperature and about 700° C. at a first cooling rate of about 5° to 1000° C./min and then cooled at a second rate ranging from said first cooling rate to water quenching to room temperature;
• and
• (f) aging the cooled article at an aging temperature in the range of 700° to 1050° C. for about 1 to 150 hours.

A process for producing fully TMT lamellar microstructure in an article of gamma titanium aluminide alloy containing 0.05 to 1.0 atomic percent boron, which comprises the steps of:

• (a) hot working the article;
• (b) pre-annealing the hot worked article at a temperature in the range of Tα−1° C. to Tα−100° C. for about 1 minute to 2 hours;
• (c) heating the pre-annealed article to annealing temperature at a rate greater than 20° C./min;
• (d) annealing the hot worked article at an annealing temperature in the range of Tα to Tα+60° C. for about 1 minute to 10 hours;
• (e) cooling said article from said annealing temperature to an aging temperature in the range of 700° to 1050° C. at a cooling rate of about 5° to 1000° C./min;
• and
• (f) aging the cooled article at said aging temperature for about 1 to 150 hours.

A process for producing fully lamellar microstructure in an article of gamma titanium aluminide alloy containing 0.05 to 1.0 atomic percent boron, which comprises the steps of:

• (a) hot working the article;
• (b) heating the said article to annealing temperature at a rate greater than 20° C./min;
• (c) annealing the hot worked article at an annealing temperature in the range of Tα to Tα+60° C. for about 1 minute to 10 hours;
• (d) cooling said article from said annealing temperature to a preselected temperature between said annealing temperature and about 700° C. at a first cooling rate of about 5° to 1000° C./min and then cooled at a second rate ranging from said first cooling rate to water quenching to room temperature;
• and
• (e) aging the cooled article at an aging temperature in the range of 700° to 1050° C. for about 1 to 150 hours.

A process for producing fully lamellar microstructure in an article of gamma titanium aluminide alloy containing 0.05 to 1.0 atomic percent boron, which comprises the steps of:

• (a) hot working the article;
• (b) heating the said article to annealing temperature at a rate greater than 20° C./min;
• (c) annealing the hot worked article at an annealing temperature in the range of Tα to Tα+60° C. for about 1 minute to 10 hours;
• (d) cooling said article from said annealing temperature to an aging temperature in the range of 700° to 1050° C. at a cooling rate of about 5° to 1000° C./min;
• and
• (e) aging the cooled article at said aging temperature for about 1 to 150 hours.