Abstract This article is based on the molecular dynamics (MD) simulation method to systematically study the effect of the phase boundary (PB) - grain boundary (GB) composite structure on the tensile strain rate sensitivity of the Biphasic fully laminar TiAl polycrystalline alloy (BFL-TiAl-PCA). By constructing multiphase models with the same grain size and orientation, the synergistic deformation mechanism, phase transition behavior, and porosity of phases/grain boundaries were analyzed in depth. The results indicate that the synergistic effect of PB and GB can effectively disperse local stress concentration, thereby improving the strength and stiffness of the alloy. Increasing strain rate narrows the performance gap between the two materials, revealing a more uniform deformation pattern. Pore growth accelerated primarily near the yield limit, while the γ/α₂ multiphase structure significantly suppressed pore coalescence. The RDF and CSP analyses revealed that high strain rates inhibit atomic disorder and dislocation nucleation, enhancing crystalline structural stability. This study elucidates the strain rate sensitivity and interface strengthening mechanisms in BFL-TiAl-PCA, providing theoretical foundations for designing high-performance lightweight structural materials.

Strain rate-dependent non-linear constitutive model of bone: From quasi-static to low-impact loading scenarios.

Microstructural evolution and adiabatic shear band formation in tempered AISI 4340 steel under high strain rate and elevated temperature impact

Interplay among temperature, microstructure and failure mechanism of the quenching and partitioning (Q&P) steel at high strain rate

Test piece design, mechanical properties and fracture strain in two-step tensile testing of lightweight materials at high strain rates

Study on electrochemical corrosion behavior and damage repair performance of Ni-La composite microalloyed Sn-Ag-Cu solder alloys at high strain rates

Dynamic response of concrete materials at high strain rates: experimental and numerical studies

Mechanical response and damage formation in short-fibre reinforced polycarbonate from low to high strain rates

Effects of shear thickening fluid filling in additively manufactured sandwich panels during intermediate and high strain rate penetration

Investigation on the spalling failure of concrete under high strain rate loading by simulation and experimental method

Flow stress and microstructural evolution of a novel Al-0.8Mg-1.0Si-0.6Cu-0.4Mn-0.1Zr alloy during high strain rate compression deformation

A unified finite strain visco-elastic visco-plastic constitutive model for a thermosetting polymer from low to high strain rates: Experiments, Validation and Bayesian optimization

Study on the mechanical and thermal coupling behavior and damage mechanism of C/SiC ceramic matrix composites under coupled loading at high temperature and high strain rate

Abstract Molecular dynamics simulations are conducted to study the grain size, temperature, and strain rate dependences of the mechanical properties and deformation mechanisms in polycrystalline hexagonal close-packed (HCP) CoCrFeMnNi HEAs under uniaxial tensile loading. Our computations reveal that the plastic deformation mechanism of polycrystalline HCP CoCrFeMnNi HEA is predominantly mediated by grain boundary motion and stacking fault generation, while dislocation nucleation and propagation play a minor role. With increasing average grain size from 3.06 to 14.20 nm, the yield strength of polycrystalline HCP HEA shows a monotonic increase, consistent with the inverse Hall-Petch relationship. The damage behavior of polycrystalline HCP HEA exhibits a distinct grain size dependence, in which smaller grains lead to uniformly distributed damage throughout the specimen but larger grains result in severe local destruction. It is revealed that the polycrystalline HCP HEA exhibits significant thermal softening at elevated temperatures and remarkable strain rate hardening at higher strain rates. Furthermore, the dependences of deformation mechanisms on the temperature and strain rate are also analyzed in detail. These findings provide fundamental insights into the mechanical properties and deformation mechanisms of the polycrystalline HCP HEAs, offering important guidance for their rational design and engineering applications.

High strain rate deformation mechanisms in fcc alloys as a function of load triaxiality

Silica-based glasses have found numerous applications in every field of human endeavor. Understanding their mechanical behavior under high strain rates is essential for the use of these materials in extreme environments. We report on a highly unusual fracture behavior observed in borosilicate glass facilitated by stress-induced molecular rearrangements, allowing the glass to withstand tensile stresses up to 11 GPa. Converging surface acoustic waves (SAW) with controlled amplitude are generated optically and used to investigate the high-strain-rate (108 s-1) fracture behavior of borosilicate glass. Above a tensile stress threshold of 6 GPa, fracture of the glass surface is observed, characterized by ejection of material and radial cracking. Unexpectedly, upon further increase of the SAW stress, a second threshold of 8 GPa tensile stress is observed above which the fracture probability dramatically decreases. Raman spectra and nanoindentation measurements of shocked samples indicate significant changes in the topology and coordination numbers of silicon and boron atoms in the amorphous network. These results suggest the ability of thresholded atomic rearrangements to serve as an intrinsic high-strain-rate toughening mechanism for enhanced fracture toughness in amorphous borosilicate glass under dynamic strain conditions.

Cold bonding between dissimilar metals and alloys offers several benefits, such as the absence of soft heat-affected zones and thick intermetallic layers with properties that differ from those of the base metals. At room temperature, thermally driven diffusion processes are negligible, but we demonstrate here that mechanically strong bonds are still feasible through high plastic deformation and high strain rates. If the strain rate is high and the temperature is kept low to avoid significant annihilation of vacancies, mechanically strong bonds involving intermetallic compound formation can still form through vacancy-driven diffusion across the contact interface. In the present investigation, two different experimental setups were employed to demonstrate strong bonding between copper and aluminium at room temperature, using phenomenological equations for excess vacancy formation and diffusion to highlight the underlying bonding mechanisms involved. Transmission electron microscopy is used to verify the bonding mechanisms.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-25620-1.

Shear bands dictate the failure mechanisms of alloys across various strain rates and limit the damage tolerance of the alloy. While short-range amorphization has the potential to mitigate shear effects, it has thus far been confined to the nanoscale. Here, we extend amorphization to the micrometer scale, fundamentally replacing shear-dominated failure in multi-principal element alloy micropillars. We implement continuous compression strain-training from low to high strain rates, generating a top-down high-density dislocation gradient that drives the formation of a topological disorder network, extending over one-third of the micropillar height, which we define as hyper-range amorphization. Within the amorphous bands, atoms exhibit dynamic disorder, and the lattice rearranges and recovers, dissipating shear stress. The alloy achieves an ultimate compressive strength of ceramic level ( ~ 6.5 GPa), while maintaining ~59.1% plasticity. This work reveals a strain engineering-based mechanical mechanism for extending amorphization, establishing it as a viable pathway to enhancing the structural stability and energy dissipation capacity of alloys.

Abstract Nanoindentation testing conducted at low and high strain rates holds great promise as a technique for measuring strain rate sensitivity and exploring the plastic deformation mechanisms of ceramic materials that cannot be studied in standard tension tests because of their inherent brittleness. In this study, we employ a high strain rate nanoindentation testing system, combined with transmission electron microscopy, to investigate the intrinsic mechanisms of plastic deformation in two ceramic materials. The investigations encompass a wide range of indentation strain rates, spanning from a low of 10 −2 s −1 to a high of 10 4 s −1 , using single crystal MgO (111) and Al 2 O 3 (0001) as model materials. The results reveal that MgO exhibits a clear dependence of hardness on strain rate, while for sapphire, the influence of strain rate on hardness is negligible. The mechanisms underlying the distinct strain‐rate responses of the two materials were revealed through microstructural investigations beneath the indent. Overall, the results demonstrate the promise that nanoindentation testing techniques have for characterizing the plastic deformation of ceramics over a wide range of strain rates.

Purpose The paper aims to evaluate the energy absorption properties of optimised strut cross-section AlSi10Mg lattice structures fabricated by laser powder bed fusion (PBF-LB) additive manufacturing (AM). Quasi-static evaluations indicate a transformation in deformation behaviour of lattices with increasing optimisation which supports strong energy absorption capabilities. Design/methodology/approach The paper applies a novel strut element optimisation method using a hybrid continuum-beam finite element model to improve energy absorption in metal lattice structures. Impact testing occurs on laser powder bed fusion (PBF-LB) fabricated aluminium alloy (AlSi10Mg) lattices specimens to validate the approach. Findings The study provides both a qualitative and quantitative understanding on how PBF-LB AlSi10Mg lattices behave at high strain rates and how strut geometry can be manipulated to produce superior as-manufactured structures. Research limitations/implications The qualification of structures produced by AM is dependent on material, structure and process technology. Further evaluation of geometric and topologic derivatives of the presented structures is required. Practical implications The paper demonstrates the refinement of lattice structures for the use as metamaterials with unique properties unattainable through conventional material science. Social implications The efficient distribution of lattice material reduces unnecessary material expenditure. Structural optimisation provides the means to further reduce expenditure for high value applications such as crash safety and biomedicine. Originality/value This study provides a method to elicit different behaviours and properties in metal lattice structures, which may lead to wide reaching applications as they become more common in engineering industry. It also provides a direct evaluation of mechanical properties of optimised metal lattice structures.