Deformation, Constitutive Behavior and Damage of Advanced Structural Materials under Multiaxial Loading.
Abstract
This report investigates the mechanisms of cyclic and monotonic deformation in nickel aluminides (Ni3Al) and nickel/aluminum as a function of loading mode (uniaxial vs. multiaxial) temperature, strain rate and environment. The program has analytical, numerical, and experimental aspects. The premise of the program is that it is important to understand these phenomena if ordered alloys are to be used in advanced jet engine components. Ordered intermetallic alloys possessing long range atomic order and forming superlattice structures are being studied for high temperature applications which are currently dominated by superalloys. These alloys generally exhibit excellent corrosion resistance and oxidation resistance at elevated temperatures. The long range order causes slower diffusion rates and thus improves creep resistance. In these structures, dislocation motion depends on various factors which either enhance or inhibit dislocation mobility depending upon temperature. The strength of these materials does not decrease drastically with temperature as seen in other disordered alloys, and in some cases the yield stress actually increases with temperature. Inspite of the desirable properties possessed by these materials, inherent brittleness has limited their applications. This brittleness is due to weak grain boundaries for NiAl and Ni3Al and limited number of permissible slip systems for NiAl.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 14, 1991
- Accession Number
- ADA239221
Entities
People
- Graham Webb
- Stephen D. Antolovich
Organizations
- Georgia Tech