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Under the guidance of materials genome engineering, Professor Zhaoping Lyu’s team has added an appropriate amount of oxygen to the equiatomic high-entropy alloy model, TiZrHfNb, from which they have discovered a new form of oxygen interstitials in alloys. The presence of such ordered oxygen complexes (OOCs) rich in O, Zr, and Ti has been verified using a scanning transmission electron microscope (STEM) with a spherical aberration correction, three-dimensional atom probe tomography (3D-APT), and first principles calculations (shown in Fig. 1). As a new interstitial state between the frequently occurring random interstitials and the ceramic phase, this ordered interstitial complex can considerably improve the strength and ductility of the alloy. In addition, it breaks the paradox of strength and ductility found in metal materials, enhancing both simultaneously; the tensile strength is increased by 48.5%, whereas the tensile plasticity is almost doubled (as shown in Fig. 2). The results, published in Nature [563(7732):546–550] on November 22, 2018 (as shown in Fig. 3), provide new ideas for the recognition of interstitial and ordered strengthening and the design of metal materials with enhanced strength and ductility.
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