Fatigue Response of Mo-Si-B Alloys
Abstract
The high-temperature compression response as well as the monotonic and cyclic crack growth behavior of a two-phase Mo-Si-B alloy compared to a TZM alloy. The compression studies confirmed that deformation in the temperature-strain rate space evaluated is matrix-dominated. In all instances evaluated, the Mo-Si-B alloys is superior to TZM. Fracture toughness of the Mo-Si-B alloy increases from ^8MPa x m at room temperature to ^25 MPa x m at l400C, the increase being steepest between l200C and l400C. S-N response at room temperature is shallow whereas at 1200C, a definitive fatigue response is observed. Fatigue crack growth in vacuum and air in the temperature interval 20C-600C is similar for the Mo-Si-B alloy whereas significant deterioration is noted for TZM when it is tested in air. The Paris slopes for the two alloys is high at room temperature (^2O-3O) and decreases with increasing temperature to 3 at 1400C. Activation energy measurements illustrate grain-boundary difflision dominance in the 900 C-l200C regime and volume difflision dominance in the 1200C-1400C regime.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2005
- Accession Number
- ADA438335
Entities
People
- K. S. Kumar
Organizations
- Brown University