Mechanical Property Characterization and Modeling for Structural Mo-Si-B Alloys for High Temperature Applications

The objective of the work described in this proposal is to aid in the advancement of Mo-Si-B alloys for use in high temperature applications such as hot gas stream components in turbine engines. Such alloys are being characterized for their monotonic tensile properties in tension and compression as well for their creep resistance. Likewise, multiphase Mo-Si-B alloys have been studied in terms of monotonic and cyclic crack growth and creep fatigue interactions. Less is known about their cyclic deformation response. Computer modeling has been applied to the Mo-Si-B alloy system. However, only 2D studies have been conducted on this material. The accuracy of prediction was found to be very good when the 2D microstructure based simulations were conducted. These studies can be extended to model the failure mechanisms with high level of accuracy because of capturing the stress profile in the material with very high level of accuracy, including the stress concentration location and magnitude and crack length for intergranular fracture. The present work will strive to develop 3D models of the alloy microstructure, and conduct analysis over a range of temperatures and strain rate; all of which are not yet available for this alloy in the existing studies.