Authors:

Allison C Renshaw

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About Paper:

Functionally graded materials (FGM) that spatially vary in composition and microstructure can offer improved mechanical performance for aerospace applications at a lower cost. Using additive manufacturing (AM) processes, these materials can be created with gradients in structural and thermal properties, enabling design interplay between structural requirements and cost. Specifically, AM processes like directed energy deposition allow for the simultaneous deposition of multiple powder compositions at adjustable rates. To create the most stable gradients in composition for the creation of FGM's, the transition path between two or more unique alloy compositions can be identified by analyzing thermodynamic property data. For this project, Thermo-Calc was used to predict thermophysical properties and phase equilibria for high temperature alloys as a function of composition and temperature. A weighted-sum model was used to identify optimal compositional pathways by minimizing differences in thermal expansivity, density, and thermal conductivity between subsequent layers, avoiding deleterious secondary phases, and accounting for the printability of each compositional step via Scheil solidification and crack susceptibility modeling. Optimal pathways between pure niobium and Ti64(Ti-6Al-4V) are shown as a proof-of-concept for utilizing thermophysical data to create stable composition gradients and demonstrate a generalizable framework that can be applied to additional alloy systems. Keywords: Functionally Graded Materials; Thermo-Calc

Source:

Purdue University / 2025

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Co-authors:

Allison C Renshaw