Modeling the effects of microstructure on the tensile properties and micro-fracture behavior of Mo–Si–B alloys at elevated temperatures

• Finite element framework developed to model deformation of Mo–Si–B alloys.
• Cohesive elements used within intermetallics and at Moss/intermetallic interfaces.
• Three-phase microstructures were instantiated using weighted Voronoi tessellation.
• Alloys have optimal strength and ductility with Moss vol. fraction in the range 0.5–0.65.

A computational framework is developed to study the role of microstructure on the deformation behavior of Mo–Si–B alloys. A parametric range of idealized multi-phase microstructures of Mo–Si–B alloys are instantiated in 2D using Voronoi tessellation schemes and their deformation behavior modeled with the use of the finite element method. Continuum elements are used to model the constituent phases, while cohesive elements are used to model debonding at the interfaces of the intermetallic (A15 and T2) phases with the solid solution-strengthened Moss matrix and cleavage fracture within the intermetallic phases. The deformation behavior of Mo–Si–B alloys is studied in terms of the simulated stress-strain response and microstructure evolution characteristics. Effects of various microstructure parameters, such as composition and clustering of intermetallic phases, on the tensile strength and ductility are also studied.