Browsing by Author "He, Z"
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- ItemIn situ neutron diffraction observations of Ti-TiB composites(Elsevier, 2019-09) Singh, H; Hayat, M; He, Z; Peterson, VK; Das, R; Cao, PThis paper characterizes and evaluates TiB/Ti composites during thermal treatment using in situ neutron diffraction. The composites were developed using a conventional press and sinter technique. Pure titanium (Ti) was chosen as the matrix, and different concentrations of TiB2 were used as the boron source for the in situ development of the TiB phase. The conversion of phases from TiB2 (2–10 wt.%) to TiB during heating and cooling in the Ti matrix was studied for the first time using in situ neutron diffraction. No metastable phases were observed during heat-treating of the samples. Microstructural evolution and tensile properties of these composites were also evaluated with the highest tensile strength recorded of 684.95 MPa for the sample containing 5 wt.% TiB2. © 2019 Elsevier Ltd
- Item(Mg,Mn,Fe,Co,Ni)O: a rocksalt high-entropy oxide containing divalent Mn and Fe(American Association for the Advancement of Science, 2023-09-20) Pu, Y; Moseley, D; He, Z; Pitike, KC; Manley, ME; Yan, J; Cooper, VR; Mitchell, VD; Peterson, VK; Johannessen, B; Hermann, RP; Cao, PHigh-entropy oxides (HEOs) have aroused growing interest due to fundamental questions relating to their structure formation, phase stability, and the interplay between configurational disorder and physical and chemical properties. Introducing Fe(II) and Mn(II) into a rocksalt HEO is considered challenging, as theoretical analysis suggests that they are unstable in this structure under ambient conditions. Here, we develop a bottom-up method for synthesizing Mn- and Fe-containing rocksalt HEO (FeO-HEO). We present a comprehensive investigation of its crystal structure and the random cation-site occupancy. We show the improved structural robustness of this FeO-HEO and verify the viability of an oxygen sublattice as a buffer layer. Compositional analysis reveals the valence and spin state of the iron species. We further report the antiferromagnetic order of this FeO-HEO below the transition temperature ~218 K and predict the conditions of phase stability of Mn- and Fe-containing HEOs. Our results provide fresh insights into the design and property tailoring of emerging classes of HEOs. © 2024 American Association for the Advancement of Science.