Quantitative and well-targeted design of modern alloys is extremely challenging due to their immense compositional space. When considering only 50 elements for compositional blending the number of possible alloys is practically infinite, as is the associated unexplored property realm. In this paper, we present a simple property-targeted quantitative design approach for atomic-level complexity in complex concentrated and high-entropy alloys, based on quantum-mechanically derived atomic-level pressure approximation. It allows identification of the best suited element mix for high solid-solution strengthening using the simple electronegativity difference among the constituent elements. This approach can be used for designing alloys with customized properties, such as a simple binary NiV solid solution whose yield strength exceeds that of the Cantor high-entropy alloy by nearly a factor of two. This study provides general design rules that enable effective utilization of atomic level information to reduce the immense degrees of freedom in compositional space without sacrificing physics-related plausibility.

Herein, we achieved a large reversible room temperature magneto-caloric effect (MCE) through synergic tuning of martensitic transformation (MT) temperatures and transition entropy change (ΔStr) via micro-alloying with transition metals (Ti, V, and Cr) in Ni45Co5Mn40Sn10 meta-magnetic Heusler alloys (MHAs). By the minor addition of TM, MT temperatures were brought down to below room temperature and ΔStr was reduced while maintaining narrow MT temperature range (ΔT) and large difference in magnetization (ΔM) of Ni45Co5Mn40Sn10 MHA. In particular, Ni43.8Cr1.2Co5Mn40Sn10 MHA exhibited a very large reversible room temperature magnetic entropy change (ΔSM) of 24.5 J/kg·K with a broad operating temperature window of ∼11 K at 5 T. Indeed, the MHA exhibited a very effective refrigeration capacity (RCeff) of 276 J/kg for 5 T, which is the largest value among the reported Ni-Mn-based MHAs. The decrease of ΔStr reduces the magnetic field required for completely reversible MT and accelerates the saturation of ΔSM, which leads to maximum RCeff value in the composition of MHA. Thus, we can conclude that smaller ΔStr with narrow ΔT and large ΔM is a key variable to develop MHA with reversible MCE under low magnetic field, which will ultimately give us a guideline for the tailor-made design of high-performance magneto-caloric materials.

An anomalous glass was discovered through high-pressure heat treatment (5.5 GPa at 850 K) followed by rapid cooling of a Zr 50 Cu 40 Al 10 metallic glass. Despite a reduction in the crystallization temperature and enthalpy, high-resolution transmission electron microscopy analysis revealed that the collected bulk sample maintained a fully amorphous structure. The density of the sample was 0.6% larger than that of the as-cast state and was even larger than that of the partially crystallized state. These results suggest the formation of an ultradense packing glass that cannot be obtained through conventional annealing. Compression test results indicated a significant increase in the Young's modulus and fracture strength, supporting the creation of an anomalous metallic glass. In addition, plasticity was observed in the treated sample. It was therefore concluded that the high-pressure heat treatment enabled the creation of a new type of glass that is normally overshadowed by the crystallized phase at atmospheric pressure. We explained the creation of the ultradense glass by introducing a pressure parameter (P) to the conventional volume (v) -temperature (T) diagram.

The work hardening behavior of bulk metallic glasses has not been previously ascribed to their intrinsic structure but rather to the introduction of other components that act as hardening elements. Here, we present clear evidence of a 2D gradient rejuvenation state that can induce tailored hardening of a monolithic bulk metallic glass. We show that the local free volume content related to the rejuvenation state controls the shear band angle and the maximum effective shear stress. Hence, shear band propagation is prohibited, and the formation of a complete shear plane transecting the whole specimen is blocked. The generation of plastic strain is accompanied by an increase in the critical shear stress, resulting in sustainable apparent hardening. In this way, we present a bulk metallic glass that has a tailored hardening mechanism and establish an experimental link between a gradient rejuvenation state and mechanical properties.

Metallurgical microstructure control of Al–Ni alloys enabled scalable and facile synthesis of large-area electrodes for alkaline hydrogen evolution catalysts comparable to conventional Pt catalysts.