Experimental & Computational Tools for the Digital Representation and Prediction of Microstructure and its Incorporation in the Designer’s Knowledge Base

The objective of the proposed research is to produce a set of experimental and software-based tools for the digital representation of microstructure and its inclusion in models that predict the performance and life of metallic alloys in structural applications. The execution of four technical tasks, each scheduled to run the full five years of requested funding, are required to achieve this stated objective. The tasks are:

i.    Materials characterization and the digital representation of microstructure
The research to be undertaken involves the enhancement of methods of materials characterization, including development of robust stereological procedures, and of the direct 3D characterization and representation of microstructure. A research tool will be developed which renders this characterization in a digital form capturing the spatially varying aspects of the microstructure.

ii.   Physics-based multiscale modeling tools
Computational tools will be developed for predicting both the evolution of microstructure as a function of heat-treatment and applied stress using phase field modeling, and also microstructure/property relationships based on coupled crystal plasticity and finite element methods.

iii.  Development of PC executable research tools
These predictive capabilities, including the capturing of the accuracy of the physics-based models by which they are trained, will be rendered as PC-executable tools using the techniques of Neural Networks and Microstructure Sensitive Design. In the short term, PC-executable tools for the prediction of properties, etc., would be developed using rules-based procedures.

iv.  Application of tools to prediction of microstructure evolution and properties
The research tools to be developed will be applied to the prediction of microstructural evolution and microstructure/property relationships in candidate alloy systems. Originally, three systems were proposed, namely a/b-Ti, Ni-base superalloys and steels (during the second two year phase of the program). However, by agreement with the Program Manager, the main focus of this part of the work will be on a/b-Ti and b-Ti alloys.