Tailoring Titanium Microstructures for Reduced Oxygen Ingress during High Temperature Applications using a Novel Microstructure-Informatics Approach

ABSTRACT: High temperature applications of titanium alloys are limited by their affinity to oxygen. In these alloys, oxygen absorption results in a brittle surface layer that has a deteriorating effect on the mechanical properties of the material. Reducing oxygen ingress into these alloys at high temperatures is essential to their cost-effective utilization in both metallic thermal protection systems and hot structure applications. One promising approach to reduce oxygen ingress (without the application of additional surface coatings) while improving high-temperature mechanical properties is to design or tailor the microstructure in the material surface layer through carefully selected thermo-mechanical surface treatments. The proposed work will develop and validate a new experimental-modeling framework for capturing the precise effect of the complex material's internal structure (i.e. microstructure) on oxygen ingress. In addition, this novel framework will allow compact representation and visualization of microstructure evolution during selected thermo-mechanical processing routes, thereby enabling identification of new promising hybrid processing routes to realize enhanced performance characteristics. The proposed work is expected to contribute a central building block for the emerging Integrated Computational Materials Science and Engineering (ICMSE) infrastructure. BENEFIT: The result of this project will be the first commercially-available Microstructure Informatics Database that objectively links the salient microstructure features, oxygen diffusivity, and thermo-mechanical processing in alpha-beta Ti alloys. The overall methodology and software tools developed by MRL may also be applied to nearly any other material system with crystalline components, with an economical number of tests and rapid characterization and analysis time. This will, in turn, open the door to the design and optimization of new high-performance materials.