A lightweight strain glass alloy showing nearly temperature-independent low modulus and high strength.

Fast development of space technologies poses a strong challenge for elastic materials, which need to be not only lightweight, strong and compliant, but also able to maintain stable elasticity over a wide temperature range1-4. Here we report a lightweight magnesium-scandium strain glass alloy (Mg with 21.3 at.% Sc) that meets this challenge. This alloy is as light (density ~2 g cm-3) and compliant as organic-based materials5-7 like bones and glass fibre reinforced plastics, but in contrast with those materials, it possesses a nearly temperature-independent (or Elinvar-type), ultralow Young's modulus (~20-23 GPa) over a wide temperature range from room temperature down to 123 K; a higher yield strength of ~200-270 MPa; and a long fatigue life of over one million cycles. As a result, it exhibits a relatively high, temperature-independent elastic energy density of ~0.5 kJ kg-1 among known materials at a moderate stress level of 200 MPa. We show that its exceptional properties stem from a strain glass transition, and the Elinvar-type elasticity originates from its moderate elastic softening effect cancelling out the ever-present elastic hardening. Our findings provide insight into designing materials that possess unconventional and technologically important elastic properties.

A biopolymer-like metal enabled hybrid material with exceptional mechanical prowess.

The design principles for naturally occurring biological materials have inspired us to develop next-generation engineering materials with remarkable performance. Nacre, commonly referred to as nature's armor, is renowned for its unusual combination of strength and toughness. Nature's wisdom in nacre resides in its elaborate structural design and the judicious placement of a unique organic biopolymer with intelligent deformation features. However, up to now, it is still a challenge to transcribe the biopolymer's deformation attributes into a stronger substitute in the design of new materials. In this study, we propose a new design strategy that employs shape memory alloy to transcribe the "J-curve" mechanical response and uniform molecular/atomic level deformation of the organic biopolymer in the design of high-performance hybrid materials. This design strategy is verified in a TiNi-Ti3Sn model material system. The model material demonstrates an exceptional combination of mechanical properties that are superior to other high-performance metal-based lamellar composites known to date. Our design strategy creates new opportunities for the development of high-performance bio-inspired materials.