Processing, Microstructures, and Properties of Nb-Based Metal/Silicide Alloys
Abstract
The Nb-Ti-Cr-Si-X alloys (X-Ht, Al, Sn, Fe, Ge) consisting of the solid solution Nb phase (Nb,s) in equilibrium with intermetallic phases ((NbTi)5Si3 and Cr2Nb) are potential candidates as hot-section materials for jet engines. The processing-microstructure-mechanical property relationship and damage/fracture mechanisms of these alloys have been investigated. Processing methods have included induction skull melting, rapidly solidified powder production by rotating electrode and gas-atomization processes, and thermomechanical processing involving hipping and hot-extrusions. Tensile, compressive, and toughness properties have been determined from room temperature to 1100 C in laboratory air atmosphere. The alloys exhibited a brittle-to-ductile transition at temperatures above 800 C. Below this temperature, premature brittle tensile failure was caused by large silicide agglomerates at fracture stress values <390 MPa. At 1000 C, the yield strengths, depending upon composition, ranged from 185 to 372 MPa, while at 1100 C, they ranged from 138 to 219 MPa. The toughness values ranged from ^10 - 17 MPavm from room temperature to 1100 C.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2003
- Accession Number
- ADA420752
Entities
People
- Madan G. Mendiratta
Organizations
- Universal Energy Systems