High-entropy herringbone alloy: Eutectic high-entropy alloys have a dual phase structure that could be useful for optimizing a material’s properties. Shi et al . found that directional solidification of an aluminum-iron-cobalt-nickel eutectic high-entropy alloy created a herringbone-patterned microstructure that was extremely resistant to fracture (see the Perspective by An). The structure contained lamellae of hard and soft phases, and the cracks that formed in the hard phase were arrested at the boundary of the soft phase. This, along with stress transfer, allowed a tripling of the maximal elongation while retaining high strength. —BG

The strength–ductility trade-off has long been a Gordian knot in conventional metallic structural materials and it is no exception in multi-principal element alloys. In particular, at ultrahigh yield strengths, plastic instability, that is, necking, happens prematurely, because of which ductility almost entirely disappears. This is due to the growing difficulty in the production and accumulation of dislocations from the very beginning of tensile deformation that renders the conventional dislocation hardening insufficient. Here we propose that premature necking can be harnessed for work hardening in a VCoNi multi-principal element alloy. Lüders banding as an initial tensile response induces the ongoing localized necking at the band front to produce both triaxial stress and strain gradient, which enables the rapid multiplication of dislocations. This leads to forest dislocation hardening, plus extra work hardening due to the interaction of dislocations with the local-chemical-order regions. The dual work hardening combines to restrain and stabilize the premature necking in reverse as well as to facilitate uniform deformation. Consequently, a superior strength-and-ductility synergy is achieved with a ductility of ~20% and yield strength of 2 GPa during room-temperature and cryogenic deformation. These findings offer an instability-control paradigm for synergistic work hardening to conquer the strength–ductility paradox at ultrahigh yield strengths.

Residual stress exists extensively in biological and engineering structures. Here we report that residual stress can be engineered to significantly enhance the strength and ductility of gradient materials. In-situ synchrotron experiments revealed that the strongest strain hardening occurred in the layer with the highest compressive residual stress in a gradient structure. This layer remained elastic longer than adjacent layers during tension, producing high hetero-deformation induced stress to increase strength and enhancing work hardening even after the disappearance of the compressive stress to increase ductility. This finding provides a new paradigm for designing gradient structures for superior mechanical properties. Impact Statement We show that compressive residual stress layer in SMAT-processed gradient material produces hetero-deformation induced hardening, which played a major role in improving strength and ductility. GRAPHICAL ABSTRACT

Conventional immunotherapy exhibits low response rates due to the immunosuppressive tumor microenvironment (TME). To overcome this limitation, this study introduces ZFPG nanoparticles (ZFPG NPs) with ZnFe₂O₄@Pt cores and glucose oxidase (GOx) shells. The ZFPG NPs possess five-enzyme activities, good sonosensitivity, and remarkable magnetic targeting properties, which facilitate sono-metallo-immunotherapy for prostate cancer treatment in male mice. Specifically, the magnetic targeting ability effectively improves their accumulation in tumors while still showing enrichment in the liver and kidneys. The multienzyme cascade catalysis and sonosensitivity of these NPs effectively deplete glutathione and glucose, and enhance the generation and utilization of H₂O₂, thereby inducing multiple ROS bursts. Furthermore, these comprehensive effects up-regulate the HMOX1 to promote the Fe²⁺ and lipid peroxides accumulation, thereby inducing immunogenic ferroptosis. This strategy facilitates anti-tumor immunity by ameliorating the immunosuppressive TME and inhibiting lung metastatic progression. This joint warfare strategy offers a powerful solution to address conventional immunotherapy limitations.