The compressive strength of the alloy is up to 2.64 GPa, surpassing other reported NTE materials.

Negative thermal expansion (NTE) materials are specialized functional materials that exhibit anomalous expansion and hold broad application prospects in high-tech fields such as precision transmission.

However, most NTE materials are intrinsically brittle intermetallic compounds with insufficient strength. Though some primary phase-transition alloys offer good mechanical properties, they suffer from inherently narrow service temperature ranges, creating an urgent need to develop NTE materials that combine ‌high strength‌ and ‌broad operational temperature windows‌ to meet these demanding requirements.

Professor Ma Tianyu's team at the Frontier Institute of Science and Technology of Xi'an Jiaotong University (XJTU) recently designed a high-strength, wide-temperature-range NTE Fe-Co-Ni-Ti compositionally complex alloy (CCA) based on multi-principal-element interaction effects.

In this system, the FCC matrix undergoes a ‌unit-cell-expanding structural transformation‌ upon cooling, generating the NTE effect. Micron-scale BCC quenched martensite and nano-scale ordered FCC precipitates provide ‌strengthening effects‌ and constrain the phase-transition kinetics of the FCC matrix, enabling both high strength and a broad service temperature range.

The study, titled Ultrastrong Negative Thermal Expansion Compositionally Complex Alloy, was published online in the top-tier materials journal Advanced Materials.