Hydrogen is well known to embrittle high-strength steels and impair their corrosion resistance. One of the most attractive methods to mitigate hydrogen embrittlement employs nanoprecipitates, which are widely used for strengthening, to trap and diffuse hydrogen from enriching at vulnerable locations within the materials. However, the atomic origin of hydrogen-trapping remains elusive, especially in incoherent nanoprecipitates. Here, by combining in-situ scanning Kelvin probe force microscopy and aberration-corrected transmission electron microscopy, we unveil distinct scenarios of hydrogen-precipitate interaction in a high-strength low-alloyed martensitic steel. It is found that not all incoherent interfaces are trapping hydrogen; some may even exclude hydrogen. Atomic-scale structural and chemical features of the very interfaces suggest that carbon/sulfur vacancies on the precipitate surface and tensile strain fields in the nearby matrix likely determine the hydrogen-trapping characteristics of the interface. These findings provide fundamental insights that may lead to a better coupling of precipitation-strengthening strategy with hydrogen-insensitive designs.

Polycrystalline SnSe is considered as a highly promising candidate for thermoelectric applications due to its facile processing, machinability and scale-up applications. Here, we report an extraordinary peak ZT of 2.4 as well as a high average ZT of 0.9 for Ge and S codoped SnSe nanorods synthesized by a facile hydrothermal route. The highly preferentially oriented SnSe nanorods along [100] play a dominant role in scattering heat carrying phonons, resulting in ultralow lattice thermal conductivity (0.15 W m⁻¹ K⁻¹ at 873 K). The band alignment in the electronic structure of SnSe is promoted by Ge doping, contributing to a giant Seebeck coefficient and a largely enhanced power factor of 5.84 μW cm⁻¹ K⁻² at 873 K. An extraordinarily high peak ZT and a high average ZT are achieved within a wide temperature range for polycrystalline SnSe without involving toxic elements. Moreover, the reported material exhibits outstanding hardness and compressive strength induced by grain refinement. The high thermoelectric performance and mechanical properties of polycrystalline SnSe open realistic pathways for its widespread application in waste heat recovery and power generation.

The high manufacturing cost for metallic glasses hampers actual commercial applications of this class of fascinating materials. In this letter, the effect of oxygen impurity on the glass forming ability and tensile properties of Zr-BMG composites were studied. Our results have demonstrated that oxygen was absorbed and concentrated only in the precipitated β-Zr phase, leading that the remainder molten metal retains good glass forming ability. The high oxygen concentration in the β-Zr phase induces a significant solid-solution strengthening effect, this resulting in an enhanced strength of the BMG composites without sacrificing their overall ductility. Based on this alloying strategy, we have successfully developed the low-cost Zr-based BMG composites with excellent tensile properties and good glass forming ability, using the low grade industrial raw materials processed under industrial vacuum systems. This finding is expected to greatly cut down the manufacturing cost and greatly promote the commercial applications of the BMG composites.

Developing alloys with both ultrahigh strength and ductility remains a formidable scientific challenge, primarily due to the inherent strength-ductility tradeoff. Here, we present an approach to enhance the ductility and strength of a medium-entropy alloy (MEA) featuring a fully recrystallized face-centered cubic/hexagonal close-packed dual-phase ultrafine-grained architecture. This is achieved by activating unusual non-basal slips in the ordered hexagonal close-packed superlattice nanoprecipitates, resulting in this MEA that exhibits remarkable uniform elongation (ε_u) and ultrahigh yield strength (σ_y) across a wide temperature range, particularly at cryogenic temperatures (σ_y ~ 2100 MPa, ε_u ~ 15%). The non-basal slips in the secondary phase are activated at ultrahigh stress levels, which are compatible with the increased yield strength of the MEA attained through multiple strengthening mechanisms, including grain boundaries, lattice friction, and second-phase nanoprecipitates provided by the multi-principal elements of the entropy alloy. The deformation mechanism elucidated in this work not only leverages the significant strengthening and strain hardening effects of brittle nanoprecipitates but also enables the ductilization of the alloy through sequential non-basal slip during ongoing deformation.