Structural materials

  • Article
    | Open Access

    While metallic glasses are expected to have tunable structures, these have rarely been demonstrated. Here, the authors combine temperature and pressure to show a two-way structural tuning in rare earth-based metallic glasses beyond the nearest-neighbor atomic shells.

    • Hongbo Lou
    • , Zhidan Zeng
    •  & Qiaoshi Zeng
  • Article
    | Open Access

    Helicoids are common structures found in many structural biological materials. Here, the authors report on a study of helicoids in the claws of scorpions and report different microstructures to what have previously been reported which have implications in materials stiffness, strength and toughness.

    • Israel Greenfeld
    • , Israel Kellersztein
    •  & H. Daniel Wagner
  • Article
    | Open Access

    3D printing of metals produces elongated columnar grains which are usually detrimental to component performance. Here, the authors combine ultrasound and 3D printing to promote equiaxed and refined microstructures in a titanium alloy and a nickel-based superalloy resulting in improved mechanical properties.

    • C. J. Todaro
    • , M. A. Easton
    •  & M. Qian
  • Article
    | Open Access

    Calcium carbonate biomineralisation has long been linked to acidic macromolecules. Here, the authors challenge this view and show that a huge number of gold nanoparticles coated with hydroxyl-rich proteins can be incorporated into a calcium carbonate crystal while maintaining single crystal character.

    • Yi-Yeoun Kim
    • , Robert Darkins
    •  & Fiona C. Meldrum
  • Article
    | Open Access

    Biology has often served as the inspiration for the design of body armor; one common limitation is the flexibility of the resultant armor. Here, the authors examine the armour of chiton and use the observed design principles to 3D print flexible armor.

    • Matthew Connors
    • , Ting Yang
    •  & Ling Li
  • Article
    | Open Access

    The glass-forming materials exhibit dynamical slowing down together with spatial heterogeneity at microscales, but their origin remains debated. Tong and Tanaka show that this phenomenon can be unified based on a structural order parameter capable of detecting subtle ordering in instantaneous liquid states.

    • Hua Tong
    •  & Hajime Tanaka
  • Article
    | Open Access

    So far, mostly 2D building blocks have been used to make origami-type multistable metamaterials that can keep their shape when deformed. Here, the authors introduce a local actuation strategy to explore the energy landscape of multistable metamaterials fabricated from 3D prismatic building blocks.

    • Agustin Iniguez-Rabago
    • , Yun Li
    •  & Johannes T. B. Overvelde
  • Article
    | Open Access

    Although polarized Raman microscopy is sensitive to orientation changes, quantitative information has been missing. Here, the authors use simultaneous registration of multiple Raman scattering spectra obtained at different polarizations and show quantitative orientation mapping

    • Oleksii Ilchenko
    • , Yuriy Pilgun
    •  & Anja Boisen
  • Article
    | Open Access

    While diamond is the strongest natural material, it fails to reach its theoretical elasticity limits and is brittle. Here, the authors show that thin <100>-orientated diamond nanoneedles can reach diamond’s theoretical strength and elasticity limits in tension.

    • Anmin Nie
    • , Yeqiang Bu
    •  & Wei Yang
  • Article
    | Open Access

    Different models are believed to be the reason for the superior mechanical properties of spider silk. Here, the authors prepare artificial spider silk by water-evaporation-induced self-assembly of a hydrogel fibre made from polyacrylic acid and silica nanoparticles.

    • Yuanyuan Dou
    • , Zhen-Pei Wang
    •  & Zunfeng Liu
  • Article
    | Open Access

    The coarsening of amorphous metallic nanoparticles remains poorly understood. Here, the authors combine high resolution microscopy and atomistic simulations to show the disordered structure of amorphous nanoparticles makes them coarsen faster than crystalline ones.

    • Yuan Tian
    • , Wei Jiao
    •  & Mingwei Chen
  • Article
    | Open Access

    Mesoscale investigations of material microarchitecture using small angle X-ray scattering (SAXS) methods have been limited by long measurement times. Here, the authors present an X-ray diffractive optics method which enables single shot acquisition of SAXS signals over large areas.

    • Matias Kagias
    • , Zhentian Wang
    •  & Marco Stampanoni
  • Article
    | Open Access

    Thermal annealing of metallic glasses is known to cause a universal increase of the relaxation time with sample age. Here, however, the authors show how a mechanical stress disrupts this universal response, leading to highly non-monotonous structural dynamics with time.

    • Amlan Das
    • , Peter M. Derlet
    •  & Robert Maaß
  • Article
    | Open Access

    Auxetic materials have usually been developed with periodically arrange structures. Here, the authors electrospin fibre networks, and show both theoretically and experimentally that these random structures have pronounced auxetic behaviour with negative out-of-plane Poisson’s ratio of large magnitude.

    • S. Domaschke
    • , A. Morel
    •  & A. E. Ehret
  • Article
    | Open Access

    Hierarchical structural materials combine organic and inorganic components to withstand mechanical impact but the nanomechanics that govern the superior properties are not well investigated. Here, the authors observe nanoscale recovery of heavily deformed nacre that restores its mechanical strength using high-resolution electron microscopy.

    • Jiseok Gim
    • , Noah Schnitzer
    •  & Robert Hovden
  • Article
    | Open Access

    Aluminium alloys can naturally age and form microstructural clusters that affect their mechanical properties. Here, the authors show that nanosized samples do not under undergo natural aging because diffusion-controlled clustering processes are inhibited.

    • Phillip Dumitraschkewitz
    • , Peter J. Uggowitzer
    •  & Stefan Pogatscher
  • Article
    | Open Access

    Here, the authors demonstrate a robotic metamaterial implemented through a combination of actuators, sensors and local controllers. They show that this active metamaterial can exhibit tunable linear non-reciprocal dynamic characteristics, with a very large and broadband non-reciprocal gain.

    • Martin Brandenbourger
    • , Xander Locsin
    •  & Corentin Coulais
  • Article
    | Open Access

    Understanding the interactions between solute atoms and crystalline defects is essential for determining alloy properties. Here the authors use a linear regression model to propose a quantitative correlation between local electronic structure descriptors and the solute-defect interaction energies in bcc refractory alloys.

    • Yong-Jie Hu
    • , Ge Zhao
    •  & Liang Qi
  • Article
    | Open Access

    Enamel is the hardest tissue in the body and has been widely studied, yet aspects of its structure remain unclear. Here, the authors report on a study of the orientation and alignment of enamel crystals and challenge previous assumptions.

    • Elia Beniash
    • , Cayla A. Stifler
    •  & Pupa U. P. A. Gilbert
  • Article
    | Open Access

    The impact of grain-scale residual stresses on the mechanical behaviour of 3D-printed metals and alloys remains unexplored. Here, the authors combine in situ synchrotron X-ray diffraction and computer simulations to link residual stresses in steel to its tensile behaviour.

    • Wen Chen
    • , Thomas Voisin
    •  & Y. Morris Wang
  • Article
    | Open Access

    Incorporating and dispersing dense nanoparticles into metals remains a challenge. Here, the authors use nanocomposite powders containing very dense nanoparticles to print an aluminium nanocomposite with one of the highest specific modulus and yield strength among all structural materials.

    • Ting-Chiang Lin
    • , Chezheng Cao
    •  & Xiaochun Li
  • Article
    | Open Access

    Wearable pressure sensors have a range of potential applications. Here, the authors develop ion pairs decorated silica microstructures embedded in an elastomeric matrix to mimic natural skin mechanoreceptors’ functions for applications in pressure-sensitive artificial skin.

    • Vipin Amoli
    • , Joo Sung Kim
    •  & Do Hwan Kim
  • Article
    | Open Access

    Understanding fast phenomena that happen in hot and opaque environments, such as during metal foaming, remains a challenge. Here, the authors use ultra-fast imaging of more than 200 three-dimensional volumes per second to explore bubble coalescence in an aluminium alloy.

    • Francisco García-Moreno
    • , Paul Hans Kamm
    •  & John Banhart
  • Article
    | Open Access

    Molecular crystals can be bent elastically by expansion or contraction on opposite faces, or plastically by delamination into slabs that glide along slip planes. Here the authors report crystals that can be bent plastically while undergoing a mechanically induced phase transition without delamination.

    • Ejaz Ahmed
    • , Durga Prasad Karothu
    •  & Panče Naumov
  • Article
    | Open Access

    The deformation of materials depends on dislocation activity, and suppressing dislocations should lead to brittleness. Here, the authors combine simulations and experiments to show a samarium-cobalt intermetallic can exhibit plasticity without dislocations.

    • Hubin Luo
    • , Hongwei Sheng
    •  & Izabela Szlufarska
  • Article
    | Open Access

    Soft actuators are typically confined to a single, predetermined deformation trajectory. Here, the authors report on a bioinspired self-adhesive material which can be attached, detached, and re-attached to expanding soft bodies to render reconfigurable and controllable deformation trajectories.

    • Sang Yup Kim
    • , Robert Baines
    •  & Rebecca Kramer-Bottiglio
  • Article
    | Open Access

    Electrochemical reactions can generate stresses that detrimentally affect battery electrodes. Here, the authors directly image the lithiation of core-shell tin-based nanoparticles and show that lithium can be redistributed by applying stress and change the nanoparticle composition.

    • Hyeon Kook Seo
    • , Jae Yeol Park
    •  & Jong Min Yuk
  • Article
    | Open Access

    Here, the authors report an effect analogous to optical activity in a 3D mechanical micro-lattice composed of chiral unit cells. They spatiotemporally resolve the motion of metamaterial beams at ultrasonic frequencies with nanometric precision and show up to 22° polarization rotation per unit cell.

    • Tobias Frenzel
    • , Julian Köpfler
    •  & Martin Wegener
  • Article
    | Open Access

    Imaging deformation twins in three dimensions is difficult and they are usually viewed as two-dimensional ellipsoids. Here, the authors statistically analyze more than two hundred deformation twins in magnesium observed in three different views and show lateral twin expansion is faster than forward propagation.

    • Y. Liu
    • , P. Z. Tang
    •  & C. N. Tomé
  • Article
    | Open Access

    3D printing pore-free complex metal parts remains a challenge. Here, the authors combine in-situ imaging and simulations to show thermocapillary force can eliminate pores from the melt pool during a laser powder bed fusion process.

    • S. Mohammad H. Hojjatzadeh
    • , Niranjan D. Parab
    •  & Lianyi Chen
  • Article
    | Open Access

    The tensile strength of a carbon nanotube fiber is predicted to increase as its constituent nanotubes become more perfectly and densely aligned. Here, the authors present an optimized direct-spinning and chlorosulfonic acid densification method to rapidly produce carbon nanotube fibers with excellent mechanical and electrical properties.

    • Jaegeun Lee
    • , Dong-Myeong Lee
    •  & Seung Min Kim
  • Article
    | Open Access

    Transparent materials with high strength and hardness coupled with low crack tolerance remain challenging to manufacture. Here, the authors develop a process to fabricate transparent but tough glass composites with a nacre-like architecture that slows crack propagation.

    • Tommaso Magrini
    • , Florian Bouville
    •  & André R. Studart
  • Article
    | Open Access

    High-entropy metallic glasses are an unexplored class of nanomaterials and are difficult to prepare. Here, the authors present an electrosynthetic method to design these materials with up to eight tunable metallic components and show multifunctional electrocatalytic water splitting capabilities.

    • Matthew W. Glasscott
    • , Andrew D. Pendergast
    •  & Jeffrey E. Dick
  • Article
    | Open Access

    Super engineering plastics that utilise bio-derived cyclic monomers rarely offer the same thermal/mechanical properties, scalability and recyclability as petrochemical derived plastics. Here the authors use a phase transfer catalyst to synthesise a transparent, recyclable and tough isosorbide-based polymer with a high molecular weight.

    • Seul-A Park
    • , Hyeonyeol Jeon
    •  & Dongyeop X. Oh
  • Article
    | Open Access

    The identification of high entropy alloys is challenging given the vastness of the compositional space associated with these systems. Here the authors propose a supervised learning strategy for the efficient screening of high entropy alloys, whose hardness predictions are validated by experiments.

    • J. M. Rickman
    • , H. M. Chan
    •  & G. Balasubramanian
  • Article
    | Open Access

    Lithium metal is the anode of choice for the next-generation high energy density batteries. To address the key technological challenges, the authors report a hybrid Li anode design with hierarchical pores structure derived from natural diatomite and improved electrochemical performance in all-solid-state lithium batteries.

    • Fei Zhou
    • , Zheng Li
    •  & Shu-Hong Yu