Effect of Heat Treatment on the Microstructure and Properties of IMI 685
IMI Ti 685 (Ti-65A1-5%Zr-0.5%Mo-0.25%Si) is a weldable near-alpha alloy which was developed for high temperature creep resistance. Maximum creep resistance is obtained by beta heat treatment, allowing the alloy to be operated at temperatures up to 520°C. The α+β/β transus temperature of the alloy is 1020°C and the commercial heat treatment consists of a solution treatment at 1050°C followed by an oil quench and a stress relieving/ageing treatment in the range 500–550°C. IMI 685 is believed to re unique in this respect in being the only transformed beta alloy in commercial use.
KeywordsCreep Resistance Quench Rate Beta Phase Alpha Phase Beta Transus
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