Heat-resistant super-dispersed oxide strengthened aluminium alloys.

Oxided-dispersion-strengthened (ODS) alloys are promising high-strength materials used in extreme environments such as high-temperature and radiation tolerance applications. Until now, ODS alloys have been developed for reducible metals by chemical processing methods, but there are no commercially available ODS alloys for unreducible metals, namely, Al, Mg, Ti, Zr and so on, owing to the challenge of uniformly dispersing oxide particles in these alloys by traditional techniques. Here we present a strategy to achieve ODS Al alloys containing highly dispersive 5 nm MgO nanoparticles by powder metallurgy, using nanoparticles that have in situ-grown graphene-like coatings and hence largely reduced surface energy.

Synergy of multiple precipitate/matrix interface structures for a heat resistant high-strength Al alloy.

High strength aluminum alloys are widely used but their strength is reduced as nano-precipitates coarsen rapidly in medium and high temperatures, which greatly limits their application. Single solute segregation layers at precipitate/matrix interfaces are not satisfactory in stabilizing precipitates. Here we obtain multiple interface structures in an Al-Cu-Mg-Ag-Si-Sc alloy including Sc segregation layers, C and L phases as well as a newly discovered χ-AgMg phase, which partially cover the θ' precipitates.

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

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.

Designing against phase and property heterogeneities in additively manufactured titanium alloys.

Additive manufacturing (AM) creates digitally designed parts by successive addition of material. However, owing to intrinsic thermal cycling, metallic parts produced by AM almost inevitably suffer from spatially dependent heterogeneities in phases and mechanical properties, which may cause unpredictable service failures. Here, we demonstrate a synergistic alloy design approach to overcome this issue in titanium alloys manufactured by laser powder bed fusion.

Effects of atom probe analysis parameters on composition measurement of precipitates in an Al-Mg-Si-Cu alloy.

Defining analysis parameter space for reliable composition measurement of materials is of significance for atom probe tomography applications. This research carefully explores the influence of specimen temperature and ultraviolet laser energy on measured compositions of precipitates and the matrix in an Al-Mg-Si-Cu alloy with atom probe tomography using voltage pulsing and laser pulsing. Low specimen temperature and high laser energy are beneficial to reduce background noise and improve mass resolution.

Rapid collagen-directed mineralization of calcium fluoride nanocrystals with periodically patterned nanostructures.

Collagen fibrils present periodic structures, which provide space for intrafibrillar growth of oriented hydroxyapatite nanocrystals in bone and contribute to the good mechanical properties of bone. However, there are not many reports focused on bioprocess-inspired synthesis of non-native inorganic materials inside collagen fibrils and detailed forming processes of crystals inside collagen fibrils remain poorly understood. Herein, the rapid intrafibrillar mineralization of calcium fluoride nanocrystals with a periodically patterned nanostructure is demonstrated.

Atom Probe Tomography Analysis of TiC Powders Synthesized by SHS in Al/Fe/Cu-Ti-C Systems.

The stoichiometry of titanium carbide (TiC) particles is important in determining particle properties. Spherical TiC powders with particle sizes of 1-5 μm were produced by self-propagating high-temperature synthesis (SHS) in 30 wt.% Al-, 30 wt.

Ultrastrong nanocrystalline steel with exceptional thermal stability and radiation tolerance.

Nanocrystalline (NC) metals are stronger and more radiation-tolerant than their coarse-grained (CG) counterparts, but they often suffer from poor thermal stability as nanograins coarsen significantly when heated to 0.3 to 0.5 of their melting temperature (T).

Self-propagating high-temperature synthesis of nano-TiCx particles with different shapes by using carbon nano-tube as C source.

With using the carbon nano-tube (CNT) of high chemical activity, nano-TiCx particles with different growth shapes were synthesized through the self-propagating high temperature in the 80 wt.% metal (Cu, Al, and Fe)-Ti-CNT systems. The growth shapes of the TiCx particles are mainly octahedron in the Cu- and Al-Ti-CNT systems, while mainly cube- and sphere-like in the Fe-Ti-CNT system.