Irradiation Enhances Strength and Deformability of Nano‐Architected Metallic Glass

Abstract

The quest for radiation-damage tolerant materials has found good candidates in nanoporous metals, whose abundance of free surfaces provides ample sinks for radiation-induced defects, as well as in metallic glasses, whose characteristic failure via shear banding can be alleviated by irradiation. This type of catastrophic failure in metallic glass can also be suppressed by reducing their dimensions to the nanoscale. To combine the beneficial effects of resilience against irradiation in materials containing many free surfaces and nano-sized metallic glasses, the authors fabricate Zr-Ni-Al metallic glass nano-architecture and irradiate them with 12 MeV Ni 4þ ions. These 3D nanolattices are composed of hollow beams of sputtered metallic glass with beam wall thicknesses %10-100 nm, with a relative density of %5%, which renders them to be 20 times lighter than their bulk-level counterparts. The authors find that the thickest-walled nanolattices, those with a median wall thickness of %88 nm, are able to withstand irradiation without significant contraction; all other substantially shrunk; and collapsed upon irradiation. In situ nanomechanical experiments on the irradiated samples compressed inside a scanning electron microscope (SEM) reveal substantial improvement in mechanical response upon irradiation, with an average increase in yield strength of 35.7% and a significant enhancement in deformability. Enhanced deformability upon irradiation is apparent from the nanolattices' accommodation of larger strains before any kind of failure, as well as the presence of smaller strain bursts and stress drops throughout the stress-strain response. The irradiated nanolattices are largely intact after compression, with in situ SEM videos demonstrating a layerby-layer like collapse in the irradiated nanolattices in contrast to the catastrophic failure with complete destruction of the failed layers observed in equivalent asfabricated samples. This work points to nano-architected metallic glasses being a promising candidate for creating ultra-lightweight, radiation tolerant materials, and irradiation as a promising technique for improving the mechanical response of metallic glass nanolattices with stiffness on the order of 250 MPa.

Three-Dimensional High-Entropy Alloy–Polymer Composite Nanolattices That Overcome the Strength–Recoverability Trade-off

“…Recent experimental studies − reported the deposition of various metals and alloys to polymer micro/nanolattices via magnetron sputtering. These experimental studies showed that the coating thickness viewed from the cross-sections of struts pronouncedly varies from the top to bottom or from the outermost to innermost regions of micro/nanolattice samples.…”

Coatings for Core–Shell Composite Micro‐Lattice Structures: Varying Sputtering Parameters

“…This area was selected for all samples as it exhibited the cleanest and clearest region via both sectioning methods. Previous studies have employed Ga þ -based FIB to expose regions of coated nanoand micro-lattice structures [1,2,36,37,[48][49][50] ; however, it has been demonstrated to yield inaccurate and obscured thickness quantifications due to damage. [2] Thus, as highlighted in Figure 4a, emerging Xe þ -PFIB technology was exercised in this study with the aim of mitigating FIB damage.…”

“…[3][4][5] However, it has been observed that sputtered coatings on complex lattice scaffolds yield large coating thickness and uniformity gradients as a consequence of the momentum-driven line-of-sight nature of the deposition technique. [1,2,36,37] In general, studies employing magnetron sputtering to generate core-shell composite nano-and micro-lattice materials have been limited to setups leveraging planar cathodes and singular sputtering conditions, which result in unidirectional deposition, a confined line-of-sight, and overall lack of sputtering parameter information. In some previous works, sample rotation has been integrated in planar sputtering assemblies with an aim to induce greater homogeneity in the coating distribution on intricate lattice structures with strut widths smaller than 1 μm.…”

Understanding the Electrical Behavior of Pyrolyzed Three‐Dimensional‐Printed Microdevices

“…With the extreme design freedom available with 2PP, there has been significant interest in its use in the fabrication of complex microscale architectures. The use of ceramics with 2PP fabrication has shown the ability to combine the increased resolution of 2PP with the robust mechanical [ 5–8 ] and chemical [ 9 ] properties of ceramics. There has also been significant work done to use 2PP as a means to additively manufacture metals to use unique phenomena which arise in metals with microdimensions and nanodimensions, such as light trapping in optical metamaterials [ 10 ] and enhanced mechanical resilience.…”