Publications by authors named "Dunji Yu"
Article Synopsis
- Iron alloys, particularly steels and magnetic materials, are crucial in various industries but struggle with high thermal expansion, limiting their precision applications.
- A new strategy has been developed to embed a nano-scale negative thermal expansion (NTE) phase within the iron matrix, effectively reducing the thermal expansion coefficient of an example alloy (Fe-Zr10-Nb6) to about half of standard iron.
- This alloy demonstrates impressive mechanical properties, achieving 1.5 GPa compressive strength and 17.5% ultimate strain, while the NTE phase helps counterbalance the thermal expansion, indicating a promising method for creating low thermal expansion iron alloys with enhanced performance.
Article Synopsis
- * A new strategy enhances the thermal conductivity and machinability of negative thermal expansion alloy (Zr,Nb)Fe by incorporating eutectic copper networks, resulting in over 200% increased thermal conductivity and improved mechanical strength.
- * The addition of copper modifies the (Zr,Nb)Fe composition, leading to better thermal management and stability across a wider temperature range, while also improving bonding and stress handling capabilities of the alloy.
Zero thermal expansion (ZTE) alloys with high mechanical response are crucial for their practical usage. Yet, unifying the ZTE behavior and mechanical response in one material is a grand obstacle, especially in multicomponent ZTE alloys. Herein, we report a near isotropic zero thermal expansion (α = 1.
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- Modern technologies require zero thermal expansion (ZTE) materials that can handle tough conditions, but many existing options have limitations.
- The research introduces a new isotropic ZTE alloy with properties like wide temperature tolerance, high strength, and thermal stability, achieved through a unique boron-migration-mediated reaction.
- The innovative "plum pudding" microstructure of this dual-phase alloy enhances its performance by eliminating crystallographic texture and improving strength and toughness, setting a new standard for ZTE material design.
Catastrophic accidents caused by fatigue failures often occur in engineering structures. Thus, a fundamental understanding of cyclic-deformation and fatigue-failure mechanisms is critical for the development of fatigue-resistant structural materials. Here we report a high-entropy alloy with enhanced fatigue life by ductile-transformable multicomponent B2 precipitates.
View Article and Find Full Text PDFMechanical characterization of micro-scale components under complex loading conditions is a great challenge. To meet such a challenge, a microtension-torsional fatigue testing apparatus is developed in this study that specializes in the evaluation of multiaxial fatigue behavior of thin stent wires. The actuation and measurement in two controlled directions are incorporated in the tensile and torsional load frames, respectively, and a thrust air bearing is applied for the coupling of the two frames.
View Article and Find Full Text PDFA portable hydro-thermo-mechanical loading cell has been designed to enable in situ small angle neutron scattering (SANS) studies of proton exchange membranes (PEMs) under immersed tensile loadings at different temperatures. The cell consists of three main parts as follows: a letter-paper-size motor-driven mechanical load frame, a SANS friendly reservoir that provides stable immersed and thermal sample conditions, and a data acquisition and control system. The ex situ tensile tests of Nafion 212 membranes demonstrated a satisfactory thermo-mechanical testing performance of the cell for either dry or immersed conditions at elevated temperatures.
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