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• Deformation kink bands were introduced, regardless of the wrought-processing. • Hardness increased with higher magnitude of applied and effective plastic strains. • Inducing shears in multiple directions were effective in enhancing mechanical properties. • Yield strength of ≥600 MPa was obtained via extrusion-torsion process. Microstructures and mechanical properties were investigated using Mg-9at.%Y-6at.%Zn alloy produced by several types of wrought-processing, i.e., forging, rolling, extrusion, equal-channel-angular extrusion, caliber rolling and high-pressure-torsion. Regardless of the wrought-processing method, deformation kink bands were induced to the long-periodic stacking ordered phase. Hardness increased with higher magnitude of applied strains. However, the inducing direction of shear strain affected the hardness values, and multiple shear strains were effective in improving the mechanical properties. For instance, the alloy produced by extrusion-torsion process exhibited yield strength in compression exceeding 600 MPa, which was over 1.7 times higher than that of the direct extruded alloy. [ABSTRACT FROM AUTHOR]

Ultrastrong metallic alloys, possessing unparalleled load-bearing abilities, are coveted in many sectors, thus attracting growing research efforts. However, these alloys encounter persistent usability challenges posed by hydrogen embrittlement, which causes unpredictable fracture through crack initiation. Due to complex hydrogen-microstructure interactions and their exacerbation under high stress, advances in hydrogen resistance in ultrastrong materials are sparse throughout their long history. Herein, we report a quantum-mechanics-informed strategy for hydrogen tolerance enhancement in ultrafine-grain-hardened Al-Zn-Mg-Cu alloys, approaching their current strength limit of approximately 1 GPa. This method involves the incorporation of hydrogen-absorbing T-phase precipitates into nanograins, to substantially reduce hydrogen coverage at potential crack initiation sites. We demonstrate, via synchrotron radiation X-ray micro-/nano-tomography, scanning transmission electron microscopy and atom probe tomography, that nanoprecipitates successfully withstand shear strains exceeding 1000 and are exploitable essentials for ultra strength-hydrogen synergy, contrasting their often-assumed secondary roles in nanocrystalline alloys due to possible strain-induced dissolution, which has intuitively excluded exploring them as central elements. Our approach potentially inspires new hydrogen-resisting alloys across a broad strength-composition space. • The first exploration into hydrogen resisting Al alloys in ultra-strength domains. • Hydrogen-trapping precipitates are incorporated into ultrafine-grained Al alloys. • T phase precipitates improve hydrogen resistance and reduces crack percentage. [ABSTRACT FROM AUTHOR]

Experiments were performed to investigate the tensile deformation characteristics of a Cu-2.5 wt% Ni-0.55 wt% Si alloy containing trace elements of Zn, Sn and Mg, processed by high-pressure torsion (HPT) under an applied pressure of 5 GPa for 10 revolutions, and then peak-aged or over-aged at 300 °C. The grain size of the HPT-processed (H) alloy was refined to 70 nm. The peak-aged (PA) alloy exhibited a higher tensile strength σ u of over 1 GPa than the H alloy. The over-aged (OA) alloy exhibited a lower value of σ u than not only the PA but the H alloy. The PA and the OA alloy revealed unique tensile deformation properties: an extremely small local elongation of 0.1% for the PA alloy, a very small uniform elongation of 0.2% for the OA alloy, and a sudden drop of tensile stress immediately after necking initiation for the OA alloy. The small local and uniform elongation for the PA and OA alloy were explained on the basis of intergranular fracture after and before necking initiation during tension. The stress drop was caused by the rapid propagation of intergranular fracture from the surface of necking part to the interior. Intergranular segregation of Sn promoted by aging at 300 °C resulted in the intergranular fracture of the PA and OA alloy. [ABSTRACT FROM AUTHOR]

Experiments were performed to investigate the tensile deformation characteristics of a Cu-2.5 wt% Ni-0.55 wt% Si alloy containing trace elements of Zn, Sn and Mg, processed by high-pressure torsion (HPT) under an applied pressure of 5 GPa for 10 revolutions, and then peak-aged or over-aged at 300 °C. The grain size of the HPT-processed (H) alloy was refined to 70 nm. The peak-aged (PA) alloy exhibited a higher tensile strength σ u of over 1 GPa than the H alloy. The over-aged (OA) alloy exhibited a lower value of σ u than not only the PA but the H alloy. The PA and the OA alloy revealed unique tensile deformation properties: an extremely small local elongation of 0.1% for the PA alloy, a very small uniform elongation of 0.2% for the OA alloy, and a sudden drop of tensile stress immediately after necking initiation for the OA alloy. The small local and uniform elongation for the PA and OA alloy were explained on the basis of intergranular fracture after and before necking initiation during tension. The stress drop was caused by the rapid propagation of intergranular fracture from the surface of necking part to the interior. Intergranular segregation of Sn promoted by aging at 300 °C resulted in the intergranular fracture of the PA and OA alloy. [ABSTRACT FROM AUTHOR]