Is alloying a promising path to substitute critical raw materials?

Abstract

A long-standing problem in metallurgy has been the alloying of metals and the search for new alloys that can improve performance and replace expensive metals. This decades-long quest for high-performance alloys has led to increasingly complex compositions. The number of possible alloy compositions to explore is literally astronomical. While this enormous range gives hope for the discovery of alternative materials, it also makes trial-and-error research highly speculative. This article will show that while alloying can offer alternatives, the supply risks increases with the number of elements involved and quickly outweigh the supply risks of the element being replaced. Therefore, the possibilities of alloying are not unlimited and a balance must be found between the overall supply risk and the number of elements used. In substitution scenarios, the supply risk increases almost linearly with the number of elements in the alloy. As a rule, effective combinations comprise no more than five elements, all of which are selected from the elements with the lowest supply risk. This significantly limits the range of possible candidates and makes the task of synthesis and characterization more manageable for materials scientists. By considering the multiple dimensions stepping in the supply risk, the list of suitable elements can be further refined and prioritized.

One sentence summary

Alloying should balance performance and element count to ensure viable materials.