Discovery of ordered interstitial atomic complexes solving the dilemma between material strength and ductility

发布日期：2019-07-25 12:33:30

Using material genome engineering, the group headed by professor Zhaoping Lu doped a model TiZrHfNb high-entropy alloy of equal atomic ratio with the appropriate amount of oxygen and discovered a previously unknown state for the interstitials in the alloy. The utilization of STEM, 3D-APT, and first-principle calculations verified the existence of the ordered oxygen complexes (as shown in Figure 1), which are rich in O, Zr, and Ti. This new interstitial state exists between the traditional random interstitial and ceramic phases and provides an alloy with significantly increased strength and ductility, overcoming the conundrum in which the strength and ductility of the metal materials cannot be obtained at the same time. A simultaneous increase in both strength and ductility has now been realized. The tensile strength is enhanced by 48.5%, whereas the ductility is almost doubled (as shown in Figure 2). This novel approach provides a paradigm shift in the interstitial ordered strengthening and ductilization, and is blazing a new path in the design of strong and ductile metal materials.

Using material genome engineering, the group headed by professor Zhaoping Lu doped a model TiZrHfNb high-entropy alloy of equal atomic ratio with the appropriate amount of oxygen and discovered a previously unknown state for the interstitials in the alloy. The utilization of STEM, 3D-APT, and first-principle calculations verified the existence of the ordered oxygen complexes (as shown in Figure 1), which are rich in O, Zr, and Ti. This new interstitial state exists between the traditional random interstitial and ceramic phases and provides an alloy with significantly increased strength and ductility, overcoming the conundrum in which the strength and ductility of the metal materials cannot be obtained at the same time. A simultaneous increase in both strength and ductility has now been realized. The tensile strength is enhanced by 48.5%, whereas the ductility is almost doubled (as shown in Figure 2). This novel approach provides a paradigm shift in the interstitial ordered strengthening and ductilization, and is blazing a new path in the design of strong and ductile metal materials. The results were published in Nature [563(7732):546—550] on Nov. 22, 2018.

Figure 1. Analysis results of 3D-APT with ordered oxygen complexes in TiZrHfNb-O2 high-entropy alloy.

Figure 2. Tensile stress–strain curves of TiZrHfNb-O(N) alloy.