Overview
Multiscale Computational Tools for Predicting Thermodynamics,
Microstructure Evolution and Mechanical Properties of Single-crystal
Ni-base Superalloys
This is a collaborative research project jointly proposed by
a group of materials scientists and physicists with complimentary
expertise in first-principles and atomistic calculations, phenomenological
computational thermodynamics, mesoscale microstructure evolution,
macroscopic mechanical property modeling, and experimental determination
of phase equilibria and high-temperature creep properties. The
main objective of the proposal is to develop a set of integrated
computational tools that can be employed to predict the relationships
among the chemistry , microstructure and mechanical properties
of single-crystal Ni-base superalloys. In particular, we will
develop:
(i) A computer technology to construct reliable thermodynamic
and kinetic databases for Ni-base superalloys by combining first-principles
calculations, the semi-empirical atomistic BFS (Bossolo-Ferrante-Smith)
method, CALPHAD (CALculations of PHAse Diagrams), and existing
thermodynamic data or proposed experimental determination of phase
equilibria in model alloy systems using the newly-developed combinatorial
approach
(ii) A phase-field technique for modeling the microstructure
evolution during high-temperature coarsening in complex, elastically
inhomogeneous, multicomponent systems, with an interface to the
thermodynamic and kinetic databases
(iii) A probabilistic creep and rupture model for predicting
the life of Ni-base superalloys using the microstructures predicted
from the phase-field as the basic input
Each of these three technologies themselves are an innovation,
comparing to existing capabilities. An integration of these computational
tools has the potential to revolutionize the design of superalloys,
and thus considerably reduce the time and cost for new superalloy
development, and to accurately predict the lifetime of superalloy
engine components. The computational models will be validated
with critical experiments on the determination of thermodynamic
data, high-temperature phase-equilibria, and coarsening kinetics
of ?' precipitates (Penn State), and high-temperature creep behavior
of single crystal Ni-based superalloys (University of Florida).
All the experimental validations will be carried out in close
collaboration with the Advanced Metals Branch of the Materials
Division at NASA-GRC and the General Electric Corporate Research
& Development Center. Model development and validation will
be performed in systems ranging from simple Ni-base binary alloys
to complex alloys such as CMSX-10.
|
