Chemical heterogeneity modulated zero thermal expansion alloy over super-wide temperature range

Chemical heterogeneity is usually avoided in solution chemistry, but it may still occur with sometimes dramatic effects on target mate-rials and their properties. Here, we propose chemical heterogeneity as a counterintuitive strategy to design high-performance zero ther-mal expansion (ZTE) alloys. We apply this approach in a Hf-Ti-Fe alloy with excess Fe in the Hf/Ti sublattice and produce Hf/Ti con-centration alternations at the micro level. Such chemical heteroge-neity regulates local magnetic interactions in alloy and triggers a dispersed magnetic phase transition that modulates the thermal ex-pansions at the micro level and hence results in a remarkable ZTE behavior over a super-wide temperature window from 10 to 480 K. This mechanism is supported by comprehensive studies on morphological microstructures, crystal and magnetic structures, and theoretical calculations. The strategy of local chemical hetero-geneity opens up an avenue to design ZTE and the related functional materials directly via microstructure engineering.

Automated summary

Chemical heterogeneity, as a counterintuitive strategy, is proposed to design high-performance zero thermal expansion (ZTE) alloys. In a Hf-Ti-Fe alloy with excess Fe in the Hf/Ti sublattice, the introduction of chemical heterogeneity at the micro level regulates local magnetic interactions and triggers a dispersed magnetic phase transition, resulting in remarkable ZTE behavior. The strategy of local chemical heterogeneity opens up an avenue to design ZTE and related functional materials directly via microstructure engineering.