On-the-Fly Path Planning for the Design of Compositional Gradients in High Dimensions

TL;DR

This paper introduces an on-the-fly path planning method for designing compositional gradients in high-dimensional spaces, significantly improving efficiency over traditional surrogate models in thermodynamic alloy design.

Contribution

It proposes a novel on-the-fly sampling approach combined with a corollary of the lever rule to enable efficient high-dimensional path planning in alloy composition design.

Findings

Achieves up to 10^6 times greater efficiency than surrogate models.

Demonstrates practical applicability in thermodynamic alloy design.

Provides quantitative benchmarks of the new method's performance.

Abstract

Functional gradients have recently experienced an explosion in activity due to advances in manufacturing, where compositions can now be spatially varied on-the-fly during fabrication. In addition, modern computational thermodynamics has reached sufficient maturity -- with respect to property databases and the availability of commercial software -- that gradients can be designed with specific sets of properties. Despite these successes, there are practical limitations on the calculation speeds of these thermodynamic tools that make it intractable to model every element in an alloy. As a result, most path planning is carried out via surrogate models on simplified systems (e.g., approximating Inconel 718 as Ni$_{59}$Cr$_{23}$Fe$_{18}$ instead of Ni$_{53}$Cr$_{23}$Fe$_{18}$Nb$_{3}$Mo$_{2}$Ti$_{1}$). In this work, we demonstrate that this limitation can be overcome using a combination of on-the-fly sampling and a conjectured corollary of the lever rule for transformations of isothermal paths in arbitrary compositional dimensions. We quantitatively benchmark the effectiveness of this new method and find that it can be as much as 106 times more efficient than surrogate modeling.