Mechanical Behavior of Titanium Aluminide under Engine Operating Conditions
Abstract
A brief study to optimize the heat treatment for a useful balance of mechanical properties in Ti-25%Al10%Nb-3%V-1%Mo (atomic percent) was conducted. The selected heat treatment consisted of solution treatment at 1115 deg C (in the alpha + beta field, about 25 deg C below the transus temperature) in vacuum for 1 hour followed by cooling to room temperature in argon, followed by aging at 760 deg C in vacuum for 8 hours, followed by cooling at room temperature in argon. This treatment resulted in fine transformed microstructure with high (25%) volume fraction of primary alpha2-phase. This treatment resulted in superior fatigue crack growth resistance while still maintaining good tensile and creep properties. This solution + age heat treatment was used for study of the effects of several factors such as temperature (25, 425, 540, and 650 deg C) , environment (air and ultrahigh vacuum), frequency (0.01 to 1 Hz), R-ratio (0.1 and 0.8), and orientation (parallel and perpendicular to the final rolling direction) on the fatigue crack growth behavior.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1992
- Accession Number
- ADA258884
Entities
People
- N. Jayaraman