A nanodispersion-in-nanograins strategy for ultra-strong, ductile and stable metal nanocomposites

Abstract

Nanograined metals have the merit of high strength, but usually suffer from low work hardening capacity and poor thermal stability, causing premature failure and limiting their practical utilities. Here we report a “nanodispersion-in-nanograins” strategy to simultaneously strengthen and stabilize nanocrystalline metals such as copper and nickel. Our strategy relies on a uniform dispersion of extremely fine sized carbon nanoparticles (2.6 ± 1.2 nm) inside nanograins. The intragranular dispersion of nanoparticles not only elevates the strength of already-strong nanograins by 35%, but also activates multiple hardening mechanisms via dislocation-nanoparticle interactions, leading to improved work hardening and large tensile ductility. In addition, these finely dispersed nanoparticles result in substantially enhanced thermal stability and electrical conductivity in metal nanocomposites. Our results demonstrate the concurrent improvement of several mutually exclusive properties in metals including strength-ductility, strength-thermal stability, and strength-electrical conductivity, and thus represent a promising route to engineering high-performance nanostructured materials.

Loss-free tensile ductility of dual-structure titanium composites via an interdiffusion and self-organization strategy

“…1 C ). The dual structure exhibits a steady strain hardening behavior (with a 5.8% ductility), i.e., Θ sustainably decreases after yielding and then enters a stable strain-softening stage until reaching the tensile plastic instability criterion ( 8 ). In comparison, the Θ value of the homostructure drops rapidly before meeting the instability criterion.…”

“…Increasing the yield strength of metals utilizing dispersive second-phase particles that impede dislocation motion is one of the most common strengthening methods. These concepts have been widely used in the room-/high-temperature strengthening of titanium, aluminum, magnesium, and copper alloys and other metallic materials ( 4 – 8 ). It has been generally recognized that the strengthening effect is usually dominated by the interaction between dislocations and the elastic strain energy generated by second-phase particles ( 9 ).…”

Phase Engineering of Nanostructural Metallic Materials: Classification, Structures, and Applications

“…The discovery of SNDP-GC materials has enabled us to approach near-theoretical strengths and to produce alloys having both high strength and high ductility. Many efforts have been devoted to revealing the interactions between supernanosized crystalline phases, and amorphous phases, and the interface effects. − Hereafter, we summarize the advantages of the SNDP-GC nanostructure in terms of mechanical properties and the deformation mechanism for hyper-strength SNDP-GC alloys.…”

“…The nanoscale precipitates act as obstacles on the dislocation slip path that impede the dislocation motion and thereby enable a high level of hardening . Nanoprecipitation strengthening was first discovered for Al alloys in the early 1900s and is now widely applied to most structural alloys, including Mg alloys, Ni alloys, Ti alloys, steel, and superalloys. − Nanoprecipitation strengthening has revolutionized the Al alloy, steel, and burgeoning aircraft industries. − Recently, a novel design concept of high entropy alloys (HEAs), based on the equimolar or near-equimolar mixing of multiprincipal elements, has received increased attention from scholars worldwide. − Specifically, the characteristics of multiple principal elements and the sluggish diffusion effect in HEAs provide an opportunity to form fine and stable nanoscale precipitates, pushing the nanoprecipitation strengthening to new high levels.…”

Strength–Plasticity Relationship and Intragranular Nanophase Distribution of Hybrid (GNS + SiCnp)/Al Composites Based on Heat Treatment

“…The soft lamellar nature of GNS presents challenges in achieving a uniform intragranular distribution while maintaining structural integrity during ball milling, resulting in an insufficient work hardening ability of GNS/Al composites [8]. Studies have shown that [40][41][42], composites with nano hard particles inside Al grains can achieve high tensile strength while maintaining high plasticity, and nano particles can also introduce high-density dislocations inside the grains, significantly improving the work hardening rate of the composites. Therefore, the introduction of a nano-scale secondary phase into GNS/Al composites by a hybrid reinforcement approach is expected to realize the comprehensive performance breakthrough of GNS/Al composites.…”