High Elastic Strain Research Articles

Deformation of Nanoglass under High-pressure Torsion

Metallic glasses are amorphous solids with metallic atomic bonds. Different from traditional crystalline metals, they have no long-range atomic order. Only short-range order on the scale of 0.5–1 nm can be detected. Because of the lack of a lattice dislocation slip system, as in crystalline alloys, metallic glasses exhibit some outstanding properties, such as high elastic strain, high hardness and high strength.

Exceptional energy absorption characteristics and compressive resilience of functional carbon foams scalably and sustainably derived from additively manufactured kraft paper

To incentivize carbon sequestration activities, kraft paper, a renewable and recyclable bioproduct that is already manufactured at scale, is proposed as feedstock for producing economically viable carbon materials. The paper was first additively manufactured into 3D open cell honeycombs and closed cell plate lattices using a sheet lamination process before being pyrolyzed into paper-derived architected carbon foams (PDACFs). In the isostress orientation, PDACFs displayed low moduli, high elastic strains (~ 30–40%) and a compressive resilience similar to graphene aerogels, but at stresses up to ~ 3 orders of magnitude higher, despite the brittle nature of the carbonized fibers. In the isostrain orientation, PDACFs exhibited better moduli (~ 1 MPa – 1 GPa), which were comparable to conventional carbon foams, and smaller elastic strains (~ 5–10%). Failure in isostrain orientation proceeded by fracture propagation through and/ or between the layers while cracks in the isostress orientation extended mainly across the layers. The strength of the PDACFs (~ 0.2 – 14 MPa) was similar in both orientations, however, likely because both interlayer and intralayer failure onset involved microscopic fractures initiating and propagating through a multitude of carbonized fiber interfaces. Notably, Honeycombs and Plate Simple Cubic PDACFs exhibited a combination of strength (> 3 MPa) and energy absorption (> 1 MJ/m 3 ; > 1 kJ/kg) not found in porous carbon materials previously, suggesting that the hierarchical arrangement of carbonized fibers within a macroscopic lattice architecture is better for dissipating energy than the tetrakaidecahedron microstructure commonly found in foams. Furthermore, as an electrode in a Li-ion battery, the carbonized cellulose making up PDACFs showed reversible specific capacities of 65–140 mAh/g at a specific current of 10 mA/g for 300 cycles, which is comparable to that of commercial lithium manganese oxide batteries and graphitic anodes derived from non-renewable polymer foams. Closed cell and open cell carbon lattices, realized through a novel additive manufacturing method and pyrolysis of eco-friendly kraft paper, displayed energy storage properties, as well as combinations of compressive resilience, energy absorption and strength unmatched by current porous carbon materials. • Novel ERASL technique was introduced to fabricate closed cell plate lattices and open cell honeycomb lattices. • Lattices were made from kraft paper and pyrolyzed into Paper-Derived Architected Carbon Foams (PDACFs). • PDACFs exhibited an unprecedented combination of strength (> 3MPa) and energy absorption (> 1 MJ/m 3 and > 1 kJ/kg). • PDACFs displayed high compressive resilience similar to graphene aerogels, but at stresses up to 1000X higher. • As a Li-ion battery anode, PDACF showed reversible specific capacities of 65 – 140 mAh/g for 300 cycles.

Phase-transforming Ag-NiTi 3-D interpenetrating-phase composite with high recoverable strain, strength and electrical conductivity

It is of particular interest to achieve high elastic recoverable strain in the electrical contact materials while maintaining good electrical conductivity and decent tensile strength. It remains a challenge, especially for bulk-sized metallic materials, as the electrical conductivity and elastic strain limit (or tensile strength) are often mutually exclusive. Here, we present a material design strategy for overcoming this conflict by developing a Ag-NiTi composite with an interpenetrating-phase architecture via infiltrating Ag melt into the partially sintered porous NiTi scaffold. The composite exhibits a good combination of properties with high electrical conductivity comparable to metals, large elastic recoverable strain superior to most of bulk-sized conductive metals as well as higher tensile strength than most of alloys/composites based on silver and other noble metals. This new finding demonstrates that the interpenetrating-phase architecture design is promising for developing new materials for electrical contact application.

Effect of energy deposition on the disordering kinetics in dual-ion beam irradiated single-crystalline GaAs

The damage induced in GaAs crystals irradiated with dual-ion beam (low-energy I2+ and high-energy Fe9+), producing simultaneous nuclear (Sn) and electronic (Se) energy depositions, was investigated using several characterization techniques. Analysis of the damage buildup shows that Sn alone (single 900 keV ion beam) leads, in a two-step process, to full amorphization of the irradiated layer (at a fluence of 1.5 nm−2) and to the development of a high (2.2%) elastic strain. Conversely, only one step in the disordering process is observed upon dual-ion beam irradiation (i.e., 900 keV I2+ and 27 MeV Fe9+, Sn&Se); hence, amorphization is prevented and the elastic strain remains very weak (below 0.2%). These results provide a strong evidence that, in GaAs, the electronic energy deposition can induce an efficient dynamic annealing of the damage created in collision cascades formed during nuclear energy deposition.

Optimization of Various Percentage of Fibers in Fiber Reinforced Composite Material Leaf Springs in Vehicles

A spring steel leaf spring is commonly used for suspension system in all types of loading vehicles due to its good stiffness and fatigue strength. Today, spring steel leaf springs are used in majority of applications but they are heavy in weight, poor in terms of gets corrosion resistance and average in ride comfort. Fiber reinforced composite material leaf spring represents a key application of composite materials in the field of automotive vehicles due to improved ride comfort and light in weight. Stiffness, fatigue life and damping capacity are the critical parameter of fiber reinforced composite leaf springs. CAE software and experimental analysis have been mainly used for design and analysis for composite material leaf springs. Saman Jolaiy et.al. [2021] focused on the damping characteristics of the composite leaf springs and worked out that fabrication of composite leaf spring with viscoelastic core(2mm) decreases the damping ratio of the leaf spring system, which results in a smooth ride. Few studies evaluated the stress distribution, deflection and fatigue life assessment of composite leaf springs reinforced with glass fibers or carbon fibers or combination of carbon lass and carbon fibers. The main objective of the present work is to optimize various percentage of fiber reinforced composite material leaf springs along with insertion of viscous core. The optimized results thus obtained show that the fiber reinforced composite leaf springs with viscous core can be a good replacement of spring steel leaf springs with overall weight reduction and better damping characteristics. Replacing spring steel leaf springs with fiber reinforced composite leaf springs will improve safety, comfort, high elastic strain energy storage capacity and durability.

High-entropy intermetallics with striking high strength and thermal stability

In this work, we report on a serious of high-entropy intermetallics (HEIs) based on CoHf-like B2 crystal structure. The microstructure evolution and mechanical properties of the targeted TiZrHfCoxNixCux alloys were detailedly investigated. In particular, the equal atomic ratio TiZrHfCoNiCu intermetallic with single-phase B2 structure shows ultrahigh compressive yield strength of 1.58 GPa and fracture strength of 2.48 GPa. It is striking that TiZrHfCoNiCu intermetallic exhibits a certain toughness and very high elastic strain limit of approximately 1.5%. Furthermore, it can maintain single-phase B2 structure and high strength after annealing at 900 °C, indicating its exceptional elevated temperature phase stability. This work not only broadens the family of high-entropy materials, but also provides a new perspective for the design of superalloys based on multi-principal element intermetallics.

TiB reinforced lattice structures produced by laser powder bed fusion with high elastic admissible strain

Triply periodic minimal surface (TPMS) titanium lattice structures produced by laser powder bed fusion (L-PBF) are promising for the future of bone tissue implant applications. However, growing concerns surrounding the cytotoxicity of Ti6Al4V and the high cost and poor wear performance of novel β titanium alloys limits their practical applications. Titanium matrix composites (TMCs) have an improved strength to stiffness ratio and wear resistance making them ideal for biomedical applications. In this work, a TiB reinforced TMC was produced in situ in L-PBF using 2 vol% boron nitride (BN) nanopowder addition with an 80% porous gyroid TPMS geometry. The lattices exhibited strength to stiffness ratio up to 2.5% with a modulus of 2.5 GPa and yield strength of 62.3 MPa, ideal for cancellous bone applications. TMC strengthening is facilitated by the high aspect ratio TiB reinforcement with best properties achieved after post process heat treatment, which increased the TiB aspect ratio and resulted in a quasi-continuous network microstructure with fine alpha Ti grains. Significant attention was given to optimisation of the L-PBF parameters to achieve a high solid density >99.5% and bulk porosity >77% close to the designed 80%. Direct contact cytotoxicity tests showed TMCs have promise as biomaterials, particularly after heat treatment which reacted residual surface BN.

Topoarchitected polymer networks expand the space of material properties

Many living tissues achieve functions through architected constituents with strong adhesion. An Achilles tendon, for example, transmits force, elastically and repeatedly, from a muscle to a bone through staggered alignment of stiff collagen fibrils in a soft proteoglycan matrix. The collagen fibrils align orderly and adhere to the proteoglycan strongly. However, synthesizing architected materials with strong adhesion has been challenging. Here we fabricate architected polymer networks by sequential polymerization and photolithography, and attain adherent interface by topological entanglement. We fabricate tendon-inspired hydrogels by embedding hard blocks in topological entanglement with a soft matrix. The staggered architecture and strong adhesion enable high elastic limit strain and high toughness simultaneously. This combination of attributes is commonly desired in applications, but rarely achieved in synthetic materials. We further demonstrate architected polymer networks of various geometric patterns and material combinations to show the potential for expanding the space of material properties.

A highly distorted ultraelastic chemically complex Elinvar alloy.

The development of high-performance ultraelastic metals with superb strength, a large elastic strain limit and temperature-insensitive elastic modulus (Elinvar effect) are important for various industrial applications, from actuators and medical devices to high-precision instruments1,2. The elastic strain limit of bulk crystalline metals is usually less than 1 per cent, owing to dislocation easy gliding. Shape memory alloys3-including gum metals4,5 and strain glass alloys6,7-may attain an elastic strain limit up to several per cent, although this is the result of pseudo-elasticity and is accompanied by large energy dissipation3. Recently, chemically complex alloys, such as 'high-entropy' alloys8, have attracted tremendous research interest owing to their promising properties9-15. In this work we report on a chemically complex alloy with a large atomic size misfit usually unaffordable in conventional alloys. The alloy exhibits a high elastic strain limit (approximately 2 per cent) and a very low internal friction (less than 2 × 10-4) at room temperature. More interestingly, this alloy exhibits an extraordinary Elinvar effect, maintaining near-constant elastic modulus between room temperature and 627 degrees Celsius (900 kelvin), which is, to our knowledge, unmatched by the existing alloys hitherto reported.

Microstructure, Mechanical and Tribological Properties of Advanced Layered WN/MeN (Me = Zr, Cr, Mo, Nb) Nanocomposite Coatings.

Due to the increased demands for drilling and cutting tools working at extreme machining conditions, protective coatings are extensively utilized to prolong the tool life and eliminate the need for lubricants. The present work reports on the effect of a second MeN (Me = Zr, Cr, Mo, Nb) layer in WN-based nanocomposite multilayers on microstructure, phase composition, and mechanical and tribological properties. The WN/MoN multilayers have not been studied yet, and cathodic-arc physical vapor deposition (CA-PVD) has been used to fabricate studied coating systems for the first time. Moreover, first-principles calculations were performed to gain more insight into the properties of deposited multilayers. Two types of coating microstructure with different kinds of lattices were observed: (i) face-centered cubic (fcc) on fcc-W2N (WN/CrN and WN/ZrN) and (ii) a combination of hexagonal and fcc on fcc-W2N (WN/MoN and WN/NbN). Among the four studied systems, the WN/NbN had superior properties: the lowest specific wear rate (1.7 × 10−6 mm3/Nm) and high hardness (36 GPa) and plasticity index H/E (0.93). Low surface roughness, high elastic strain to failure, Nb2O5 and WO3 tribofilms forming during sliding, ductile behavior of NbN, and nanocomposite structure contributed to high tribological performance. The results indicated the suitability of WN/NbN as a protective coating operating in challenging conditions.

Metastable Ti-Fe-Ge alloys with high elastic admissible strain

Iron is employed as an alloying element in powder metallurgy Ti alloys for healthcare applications owing to its fast diffusion which aids sintering, excellent biocompatibility, and cost-effectiveness. In this study, we assess the use of Ge to enhance the sintering and mechanical properties of a Ti-7Fe based powder metallurgy alloy (Ge = 0, 2, and 4 wt.%). Germanium is an α-stabilising element with good solubility in the Ti matrix and possesses better biocompatibility than the commonly used aluminium α-stabiliser. After sintering, all alloys exhibited dual-phase microstructures (α and β phase), while an intermetallic Ti5Ge3 also formed in Ti-7Fe-4Ge. Despite being an α-stabilising element, germanium primarily segregated to the β phase regions in the Ti-7Fe-xGe alloys. Gradual increments of the sintered density of the alloys were observed with increasing Ge additions. The sintered Ti-7Fe-xGe alloys were solution treated to exploit the metastability of the retained β phase. After solution treatment at 1000 °C, the alloys predominantly exhibited β phase with minor traces of martensitic athermal ω-phase. Germanium suppressed the formation of the athermal ω-phase and reduced the stability of the β phase. The solution-treated Ti-7Fe-2Ge alloy is most promising for implant applications with a relatively low compressive Young's modulus (∼ 70 GPa) and high yield strength (∼ 1450 MPa), which leads to an outstanding elastic admissible strain of ∼ 2.2%.

Achieving a combination of decent biocompatibility and large near-linear-elastic deformation behavior in shell-core-like structural TiNb/NiTi composite

As expected from the material design, a novel shell-core-like structural TiNb/NiTi composite possessing both decent biocompatibility and large near-linear-elastic deformation behavior (namely as near-linear elasticity accompanied by high elastic strain limit) was prepared successfully by a hot pack-rolling combined with cold rolling procedure. Non-cytotoxic TiNb outer shell obstructs the NiTi inner core from cells and provides the decent biocompatibility of TiNb/NiTi composite. Large near-linear-elastic deformation behavior for this TiNb/NiTi composite has been confirmed to be associated with intrinsic elastic deformation, two types of reversible stress-induced martensitic transformations (i.e. β↔α'' and B2↔B19′ transformations) occurring in a homogeneous manner, together with the (001) compound twin in B19′ martensitic plates. Our study provides a new design approach for developing NiTi-based composites with both decent biocompatibility and large near-linear-elastic deformation behavior for biomedical or engineering applications.

Fracture Analysis of Vacancy Defected Nitrogen Doped Graphene Sheets Via MD Simulations

The novel hexagonal monolayer sheet of carbon atoms, graphene, has attracted great attention due to their exceptional electrical and mechanical properties. Their phenomenally high strength and elastic strain, nevertheless, can be altered by structural defects due to stress concentration. In this paper, the fracture behaviour of graphene sheets and nitrogen doped graphene sheets with vacancies were investigated using molecular dynamics (MD) simulations at the different temperatures of 300K, 500K, and 900K. The results reveal a significant strength loss caused by both the defects and vacancies and doped nitrogen in graphene. The deformation process of graphene at various strain rate levels, with regard to the failure behaviour, is discussed. The validity of the proposed MD simulations is verified by comparing the simulation results with the available predictions from the quantized fracture mechanics.

High-throughput determination of the composition-dependent mechanical and diffusion properties in β Ti–Nb–Zr–Hf refractory alloys

A combinatorial method by integrating the diffusion couple, nanoindentation, and electron probe microanalysis (EPMA) techniques and the pragmatic numerical inverse method can offer a great promise of mapping the mechanical and diffusion properties in multicomponent alloys with various compositions, which is very vital for the selection of refractory alloys in biomedical and aerospace applications. In this work, 6 groups of bcc Ti–Nb–Zr–Hf diffusion couples were prepared after annealing at 1273 K for 25 h. Subsequently, the composition-mechanical property relationships in a wide composition space of Ti–Nb–Zr–Hf system were obtained by using EPMA and nanoindentation probes. Moreover, the interdiffusion coefficients of bcc Ti–Nb–Zr–Hf alloys at 1273 K were determined by a pragmatic numerical inverse method. Finally, a composition-dependent mechanical property database of Ti-rich Ti–Nb–Zr–Hf system was established, and several characteristics on the wear resistance, elastic property, elastic admissible strain, and processability during the hot service were discussed. The results reveal that Ti–Nb–Zr–Hf alloys have high hardness, good wear resistance, and high elastic admissible strain, which can be utilized as promising alloys with optimum integrated properties for biomedical applications.

Biodegradable Metallic Glass for Stretchable Transient Electronics.

Biodegradable electronics are disposable green devices whose constituents decompose into harmless byproducts, leaving no residual waste and minimally invasive medical implants requiring no removal surgery. Stretchable and flexible form factors are essential in biointegrated electronic applications for conformal integration with soft and expandable skins, tissues, and organs. Here a fully biodegradable MgZnCa metallic glass (MG) film is proposed for intrinsically stretchable electrodes with a high yield limit exploiting the advantages of amorphous phases with no crystalline defects. The irregular dissolution behavior of this amorphous alloy regarding electrical conductivity and morphology is investigated in aqueous solutions with different ion species. The MgZnCa MG nanofilm shows high elastic strain (≈2.6% in the nano‐tensile test) and offers enhanced stretchability (≈115% when combined with serpentine geometry). The fatigue resistance in repeatable stretching also improves owing to the wide range of the elastic strain limit. Electronic components including the capacitor, inductor, diode, and transistor using the MgZnCa MG electrode support its integrability to transient electronic devices. The biodegradable triboelectric nanogenerator of MgZnCa MG operates stably over 50 000 cycles and its fatigue resistant applications in mechanical energy harvesting are verified. In vitro cell toxicity and in vivo inflammation tests demonstrate the biocompatibility in biointegrated use.

High elasticity of CsPbBr3 perovskite nanowires for flexible electronics

Due to the enhanced ambient structural stability and excellent optoelectronic properties, all-inorganic metal halide perovskite nanowires have become one of the most attractive candidates for flexible electronics, photovoltaics and optoelectronics. Their elastic property and mechanical robustness become the key factors for device applications under realistic service conditions with various mechanical loadings. Here, we demonstrate that high tensile elastic strain (∼ 4% to ∼ 5.1%) can be achieved in vapor-liquid-solid-grown single-crystalline CsPbBr3 nanowires through in situ scanning electron microscope (SEM) buckling experiments. Such high flexural elasticity can be attributed to the structural defect-scarce, smooth surface, single-crystallinity and nanomechanical size effect of CsPbBr3 nanowires. The mechanical reliability of CsPbBr3 nanowire-based flexible photodetectors was examined by cyclic bending tests, with no noticeable performance deterioration observed after 5,000 cycles. The above results suggest great application potential for using all-inorganic perovskite nanowires in flexible electronics and energy harvesting systems.

Friction surfacing of AISI 904L super austenitic stainless steel coatings: Microstructure and properties

Microstructure, texture, pitting corrosion resistance and hardness of surfaces and cross-sections of the friction-surfaced (FSed) super austenitic stainless steel 904L coatings fabricated at various spindle speeds were investigated. The microstructure of the coatings was governed by both dynamic recovery (DRV) and continuous dynamic recrystallization (cDRX) owing to the high stacking fault energy (SFE) of 904L. The grain orientations in DRV were in A 2 ⁎ shear texture component, while the rotated cube textures were related to the cDRXed grains. Immersion tests of the FSed coatings in 3.07 mol/L Cl − solution showed that the corrosion pits were slightly preferred to generate at the {111} DRVed grains on the coating surfaces, since these grains were likely to have a higher elastic strain during FS. Compared with AISI 304, the pitting potential of the FSed coatings in 3.5 wt% NaCl solution was significantly shifted to nobler direction and also insensitive to spindle speed owing to the high SFE of 904L. However, the passive films of the FSed coatings were thinner and more difficult to reform, as evidenced by slightly larger average pit diameters and lower protection potentials owing to the high residual stress caused by FS. • Microstructures of FSed 904L coatings were governed by DRV in A 2 ⁎ shear component and cDRX in rotated cube textures. • Increment of spindle speed tended to enhance cDRX but suppress DRV at the same time. • The FSed coatings could maintain excellent pitting corrosion resistance of as-received 904L. • Due to high SFE of 904L, elastic strain in {111} grains was reduced. • Crystallographic effect on pitting cororsion resistance of the coatings was weakened. • Increase in misorientation density induced by cDRX led to hardness improvement and ductility reduction for the coatings

A porous self-healing hydrogel with an island-bridge structure for strain and pressure sensors.

Conductive hydrogels have attracted widespread attention in wearable electronic devices and human motion detection. However, designing self-healing hydrogels with high conductivity and excellent mechanical properties remains a challenge. In this work, polyvinyl alcohol/carbon nanotubes/graphene (PVA/CNTs/graphene) with an island-bridge hydrogel structure and self-healing properties was designed by merging PVA/CNTs hydrogel and PVA/graphene hydrogel, in which the PVA/graphene hydrogel acts as an "island" and PVA/CNTs hydrogel acts as a "bridge" to bridge the entire conductive network. Hydrogen-bonding between the borate ion and the -OH group of PVA allows the conductive hydrogel to heal without any external stimulation. The PVA/CNTs/graphene hydrogel can be used for both stretchable strain and pressure sensors. The obtained PVA/CNTs/graphene composite hydrogel exhibits excellent electrical conductivity, extreme high elastic strain (up to 900%) and strong mechanical pressure (up to 10 kPa). The strain sensor based on the PVA/CNTs/graphene hydrogel exhibits excellent tensile strain sensitivity (a gauge factor of 152.6 in the strain region of 316-600%) and wide detection working range (1-600%) with high durability and repeatability. The sensor also remains highly sensitive when being used as a pressure sensor (-0.127 kPa-1 at 0-5 kPa). Additionally, the PVA/CNTs/graphene hydrogel-based sensor can detect human motions after multiple cuts and self-healing with excellent stability and repeatability. The PVA/CNTs/graphene hydrogel provides a new idea in the development of wearable electronics, demonstrating the potential of the next generation of wearable electronics.

Alloy design of metastable α+β titanium alloy with high elastic admissible strain

Owing to the high production cost of a high alloying system, the commercialization of β-Ti alloys with high elastic admissible strain (= yield strength/elastic modulus) for biomaterials is challenging. To reduce the alloying elements and maintain a high elastic admissible strain, a new alloy design of the metastable α+β-Ti alloy (Ti–4Al–2Mo–2Fe–2Cr) is proposed in this study. The microstructure of the alloy consists of an α phase with a high yield strength and a metastable β phase with a low elastic modulus. The existence of the hard α phase increases the critical stress for stress-induced martensitic transformation due to stress and strain partitioning. In addition, heat treatment in the α+β regime is an effective method for grain refinement, resulting in high strength without increasing the elastic modulus. This alloy exhibited an excellent combination of strength and ductility with a high elastic admissible strain. Moreover, electron backscattering diffraction and field-emission transmission electron microscopy were used to understand the mechanical behavior of the α+β Ti alloy.

DLC (H) coated 13Cr SMSS by high-pulsed power CVD technique

ABSTRACT Hydrogenated diamond-like carbon (DLC: H) films were successfully fabricated on the surface of 13Cr super martensitic stainless steel by high-pulsed power chemical vapour deposition. The mechanical and tribological properties of the films related to the substrate bias voltages were investigated. The results showed that the surface hardness and tribological properties of the substrate after DLC film deposition were improved. The DLC films became dense, the grain size and roughness reduced, and the deposition rates increased as the bias voltage increased. In addition, the dense DLC films directly led to high nanohardness and elastic modulus. The H content decreased with an increase in the bias voltage, which may be the primary reason for nanohardness and modulus enhancement. Due to the relatively high H/E* and H 2/E*3 ratios of films corresponded to high elastic strain and plastic deformation resistances reduced the wear loss, and the localized graphitization on the surface provided solid lubrication.