Significant Reduction In Tensile Strength Research Articles

Preparation of environmentally friendly ionic liquids-toughened polylactic acid/nanofibrillated cellulose composites with high strength and precipitation resistance

Polylactic acid (PLA) is one of the most promising biodegradable materials, but poor toughness severely limits its application. Ionic liquids (ILs) have excellent plasticizing effects on PLA, but strength reduction and plasticizer precipitation remain worrisome. Herein, nanofibrillated cellulose (NFC), with excellent morphology, high modulus and strength, was prepared to reinforce PLA plasticization systems. Moreover, its numerous surface hydroxyl groups were tailored to bond with ILs, reducing plasticizer precipitation. The different sulfonation degrees of NFCs (low LSNFC, medium MSNFC, high HSNFC) and the influence of NFC amounts (0–7 wt%) on the mechanical, thermal and plasticizer precipitation properties of PLA composites were investigated. The results indicate that network-like C2/C3-sulfonated NFCs were successfully prepared through simple processing steps. Noteworthy, the tensile elongations of PLA composites increased with the addition of IL-XSNFC (all three degrees), with no significant reduction in tensile strength and modulus. The addition of 7 wt% IL-HSNFC resulted in an elongation of 25.01 % for PLA composites, which is 3.6 times that of pure PLA. Adding 3 wt% IL-MSNFC achieved ultra-high impact toughness of 3.19 kJ/m2, nearly double that of pure PLA. Interestingly, with increasing sulfonation degree, the amount of ILs precipitation in PLA composites significantly decreased. The precipitation rate of the PLA composite with IL-HSNFC is only 24 % of the counterparts with IL-NFC. This work presents an innovative method to improve interface compatibility, providing a new strategy to reduce plasticizer precipitation and broaden the application scope of PLA.

Accelerated aging tests of large-diameter GFRP bars in alkaline environment

Fiber reinforced polymer (FRP) bars have become increasingly popular, while the studies on durability of FRP bars are primarily on small-diameter FRP bars. This study investigated the tensile strength retention in glass FRP (GFRP) bars of different diameters (13 mm and 25 mm) after immersion in an alkaline solution (pH=12.6) at various temperatures (20 °C, 40 °C and 60 °C) for 1, 2, 3, and 6 months. The results reveal that the degradation of GFRP bars was slow at 20 °C, accelerated but not pronounced at 40 °C and considerable at 60 °C. Particularly, the 13 mm diameter GFRP bars exhibited a more significant reduction in tensile strength, with a decrease of 20.12 % after 6 months, while the 25 mm diameter bars only decreased by 13.23 %. Results reveal that, importantly, degradation of GFRP bars is primarily attributed to the diffusion of the moisture and alkalis, which disrupts the bond between the fibers and the matrix, causing interface damage. Finally, based on the Arrhenius theory, it is predicted that the tensile strength retention of 13 mm and 25 mm diameter GFRP bars will be 66.4 % and 79.8 %, respectively, after 50 years of exposure at an average annual temperature of 35 °C. The important finding that the small-diameter FRP bars are more vulnerable to the alkaline exposure than larger diameter bars suggests that the current studies on durability of FRP bars are conservative to be referred in practice.

In-situ study of microstructure and mechanical properties of GH3536 alloy manufactured by selective laser melting at 750 °C

Nickel-based GH3536 alloy exhibits high strength but low ductility when produced by selective laser melting (SLM), which hinders its widespread application in aerospace. This paper employed a ‘two-step’ method of heat treatment to optimize the microstructure of the SLM GH3536 alloy and investigated the mechanical properties. Tensile tests were conducted on SLM GH3536 alloy before and after heat treatment at 750 °C, using an in-situ high-temperature tensile stage. The relationship between the microstructural evolution and deformation behavior of the alloys was investigated by combining the in-situ tensile experiments and crystal plasticity finite element method (CPFEM). The results suggested that the elongation can be increased by 80% without a significant reduction in tensile strength. The improved elongation is attributed to the complete recrystallization, formation of annealed twins and serrated grain boundaries after heat treatment. The study also investigated the deformation behavior and fracture mode of the alloy before and after heat treatment. Discussion was done on the influence of the microstructure, particularly the twin and serrated grain boundaries on the alloy's plastic deformation. This study enhanced the understanding of plastic deformation of SLM GH3536 alloy and provided a valuable reference for the design and post-treatment of superalloy.

Effects of ZnO/trimethylsilyl cellulose nano-composite coating on anti-UV and anti-fungal properties of papers

Trimethylsilyl cellulose (TMSC) was employed as the coating matrix for the application of zinc oxide nanoparticles (ZnO) onto paper surfaces and the protections of ZnO/TMSC coating against UV-induced damages and fungal spoilage were evaluated. Filter papers were immersed in 2% w/v TMSC solution loaded with ZnO and air-dried. Three ZnO/TMSC suspensions were prepared with 0.1, 0.5, and 1% w/v ZnO NPs. The presences of ZnO/TMSC protective layers were confirmed with ATR-IR spectroscopy. The coated papers exhibited high surface hydrophobicities. After the coated papers were subject to 365-nm UV irradiation at 400 W for 3 h, the contact angles dramatically dropped. The trimethylsilyl (TMS) groups exposed on the surface formed a moisture barrier and were partially removed on UV exposure. ATR-IR revealed that more TMS groups were removed in the protective layer with no ZnO. UV-irradiated papers turned yellow and papers protected with 1% ZnO/TMSC exhibited significantly lower color changes than that of the uncoated one. Compared to the TMSC-coated paper, the addition of ZnO resulted in a significant reduction in tensile strength at maximum. However, after UV irradiation, significant increases in both the strain at break and strength at maximum were only observed in 1% ZnO/TMSC-protected papers. Regarding their anti-fungal properties, the 1% ZnO/TMSC films were effective in growth inhibitions of Aspergillus sp. and Penicillium sp. on the nonirradiated papers. Despite being hydrophilic after UV-irradiation, growths of the molds were severely suppressed on the UV-irradiated paper.

Deformation behaviour, microstructure evolution and dynamic recrystallization mechanism of AZ31 magnesium alloy under co-extruded by Mg-Al composite billet

Conventional methods for hot extrusion of magnesium (Mg) alloy sheets have limitations for microstructure improvement and mechanical property enhancement. Co-extrusion of Mg alloy with an Al alloy core provides an opportunity for refining the grain size and improving basal texture. This study introduces a novel severe plastic deformation (SPD) method, Direct Extrusion-Continuous Shear (DE-CS), utilizing 6063 Al alloy as the core to fabricate innovative Mg/Al clad composite sheets. Monolithic Mg sheets (non-co-extruded condition) are extruded under identical conditions for comparison. By evaluating the microstructure and mechanical properties of AZ31 Mg alloy under co-extrusion and non-co-extrusion conditions, the positive effect of Mg-Al composite billet co-extrusion on AZ31 Mg alloy is established. The grain refinement effect in co-extruded samples is superior, enhancing plasticity without significant reduction in tensile strength. The microstructure evolution and dynamic recrystallization (DRX) behaviour of AZ31 Mg alloy during co-extrusion were analyzed comprehensively. The results indicate that, in the initial stages of deformation, various variants of {10−12} extension twins (ETs) play a crucial role in refining the original grains, forming initial [10−10]//ED fiber texture components alongside other non-basal components. Upon entering the shear deformation (SD) zone, deformed twins disappear, and small dynamically recrystallized (DRXed) grains emerge along boundaries of coarse deformation grains and within the grains. Strong shear deformations and compressive stress from transverse direction (TD) induce intensified prismatic <a> and pyramidal <c+a> slip, promoting continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). CDRX predominantly affects elongated deformed grains, forming an [10−10]//ED fiber texture through high-energy grain boundary segmentation. Subsequently, compatible stress increases due to the activity of non-basal slip dislocation and the reduction in grain boundary (GB) size. DDRX emerges as the dominant mechanism, generating randomized [10−10]//ED fiber and non-fiber textures within parent grains and at boundaries.

An investigation on effect of ultraviolet (UV) rays on mechanical properties of epoxy laminates

The use of epoxy resins has significantly grown in many industrial applications due to their exceptional mechanical and chemical properties. However, their susceptibility to Ultraviolet (UV) light damage and exposure to outdoor weather conditions remains a major limitation. In order to address this drawback, UV absorbers have been frequently employed to reduce the rate of UV degradation. This study investigates the impact of UV radiation on the physical, chemical, and mechanical characteristics of cured epoxy laminates. The results indicate that UV radiation causes a significant reduction in tensile strength by 22.6% after 180 h of exposure. Furthermore, UV–Visible and Fourier-transform infrared spectroscopy (FTIR) spectroscopy measurements demonstrate significant chemical and optical modifications in the epoxy matrix, leading to the deterioration of its properties. These findings provide valuable insights for designing new epoxy formulations that can withstand harsh environmental conditions and improve the durability and performance of epoxy-based products.

Toughened transparent poly(L-lactic acid)/poly(D-lactide)-b-poly(butadiene)-b-poly(D-lactide) blended film with balanced strength

Tough and transparent poly(L-lactic acid)/poly(D-lactide)-b-poly(butadiene)-b-poly(D-lactide) (PLLA/PDLA-PB-PDLA) film with balanced strength was obtained. The PDLA-PB-PDLA triblock copolymer was firstly synthesized by ring-opening polymerization (ROP) of D-lactide using bihydroyl-terminated polybutadiene as macroinitiator, and then the obtained triblock copolymer was mixed with PLLA in solution. The blended films kept in good transparence even when the loading of PDLA-PB-PDLA reached to 15 wt%. Meanwhile, the elongation at break of the PLLA/PDLA-PB-PDLA film increased by ∼10 times without a significant reduction in tensile strength as compared with that of pure PLLA. The mechanical property was ascribed to the synergetic effect of the flexible PB chains and the stereocomplex crystals formed between PLLA matrix and PDLA chains. “Salami-like” dispersed-phase with nanometer scales was observed, which would contribute to the transparency of the blended film. The tensile fractured morphologies indicated that shear yield of the matrix and cavitation might be the major toughening mechanism of PLLA/PDLA-PB-PDLA film.

On Mechanical Response of Aluminum Alloys in Corrosive Environment

Al6061T6 and Al7075T6 aluminum alloys are subjected to accelerated salt spray corrosion to evaluate the amount of degradation and the effect on mechanical behavior. The specimens were stored in a closed chamber with continuous salt spray for a period of 250 hours and 500 hours, respectively. It was observed that the oxide layer was unprotective after prolonged salt spray resulting in pitting continued with exfoliation corrosion. The tensile test results show that there was a remarkable decrease in tensile properties with exposure time. A significant reduction in tensile strength, yield strength, elongation at yield, elongation at break, and overall toughness in both the alloys was observed at 500 hours. The impact strength decreased by 14.4 % and 26.47 %, Rockwell hardness (HRB) reduced by 12.2% and 20.71% for respective alloys at 500 hours of exposure. However, there was an increasing trend in elastic stiffness which attributed to decrease in ductility. Furthermore, it was comparatively observed that Al7075T6 is more susceptible to corrosion than Al6061T6.

Development of Ficus carica Linn leaves extract incorporated chitosan films for active food packaging materials and investigation of their properties

The serious problems caused by extensive usage of petroleum-based plastic materials led to investigating the comprehensive studies and developing active food packaging materials. Even if the chitosan-based films are considered an attractive source, they exhibit some practical difficulties in developing active food packaging applications. Hence, Ficus carica Linn leaves extract (FLE), with the features of its cheapness, easy accessibility and superoxide anion radical scavenging activity, was incorporated into chitosan (CS) film at various concentrations (2%–6% w/w). To the best of our knowledge, this was the first time that FLE was utilized as a bioactive substance incorporated into chitosan films to develop eco-friendly, biodegradable, active food packaging material. The results obtained revealed that FLE incorporation into chitosan films significantly improved the swelling, water solubility and opacity of neat chitosan films. FTIR and morphological analysis indicated that the films produced exhibited smooth structure with homogenous dispersion of FLE. In mechanically, the addition of FLE resulted in a significant reduction in tensile strength while the elasticity of the films was improved. Additionally, the antioxidant and biodegradability properties of neat chitosan films were enhanced significantly. It was concluded that CS-FLE films appeared to be a capable and enhanced option for synthetic polymer-based food packaging materials. Based on the analyses performed, further studies are suggested on the packaging application for various foods and to evaluate the possible interaction of packaging film materials with the compounds of the food products, to avoid possible negative effects.

Comparison between tensile characteristics of various suture materials with two suture techniques: an in vitro study.

The first objective of the present study was to evaluate the tensile strength and elongation to failure of commonly used suture materials in oral surgery. As a secondary objective, it was aimed to make a comparison between two different suture techniques within the same suture materials. Eight different suture materials with 3-0 gauge (silk, polytetrafluoroethylene, polypropylene, polyester, polyglactin 910, polyglycolic acid, poliglecaprone 25, polydioxanone) underwent tensile testing for maximum load of failure and elongation rate. All strands were tied by one investigator on the experimental platform using the surgeon's knot plus additional square knots in both simple suture and horizontal mattress suture techniques. Prepared specimens were examined using a microtensile testing device before (baseline) and after 3, 7, and 14 days' immersion in artificial saliva. Statistical analysis of the current study revealed that the tensile strength for polyglycolic acid, polyglactin 910, polypropylene, and silk sutures was significantly lower at day 3 than at the baseline. By day 14, polyglycolic acid and polyglactin 910 showed a significant reduction in tensile strength for both techniques. While polydioxanone obtained the highest tensile strength and elongation values in both techniques, polytetrafluoroethylene showed the most stable tensile strength even with the lowest value. Tensile strength in simple suture techniques was almost twice than that of horizontal mattress suture technique for each specimen. Polyglycolic acid and polyglactin 910 were considerably sensitive to immersion time. Polydioxanone demonstrated optimum performance during each immersion period among the tested materials, whereas polytetrafluoroethylene was the most stable. The selection of the most proper suture material remains challenging for clinicians. The present study provides relevant information for clinicians to guide them in their choice of the suitable material. In this context, clinicians can benefit from the use of polydioxanone for its high tensile strength regardless of the suture technique used, whereas polytetrafluoroethylene shows a long-term stability. The strength and stability differences among suture materials and techniques need to be considered before making an informed decision.

Surface damage evaluation and computational modelling of clinically failed knee liners

ABSTRACT Five retrieved knee liners made of cross-linked, ultra-high molecular weight polyethylene were investigated. Each liner was examined by five investigators and in vivo damage was evaluated using four methods (Wasielewski, Brandt, Lombardi, and Hood). Both optical and confocal microscopy techniques were used to quantify damage modes. Oxidation index, crystallinity and hardness parameters were calculated for material characterization. Gait profiles of two subjects (one male and one female) for three different activities were considered in finite element analysis (FEA) simulations. The main hypotheses of this study were that 1) the wear tracks on the liners may be represented by maximum von Mises stress areas, 2) a single composite index may be used to represent 10 different damage modes. Significant reduction in tensile strength was observed with an average value of 27.7 MPa at 50KGy due to oxidation in all the liners. Correlations were made between FEA results and surface evaluation results. Gait analysis of the liners showed males typically have a higher stress level in vivo than females, leading to increased wear. Attempts were made to relate the damage patterns on the liners with the stress development and the damage evaluation methods and our computational simulation validates the methods that we used. Higher stress areas were compared against the surface evaluation results, showing those regions experiencing the high stress also had a high damage index. Even though the liners were mechanically intact, they failed clinically and more likely due to abrasive wear (due to third-body wear particles).

Effect of surface treatment on moisture absorption, thermal, and mechanical properties of sisal fiber

Natural fibers are increasingly being used as composite reinforcement for both thermoplastic and thermoset resin, mainly for automotive application. Due to their hydrophilic nature, natural fibers have certain limitations during composite manufacture especially owing to their poor resin wettability, weak fiber–polymer interface, high moisture absorption, and being affected by high temperature in case of thermoplastic resin. This work investigates the impact of sisal fiber modification techniques on moisture absorption, thermal, and mechanical properties of the fiber. Four sisal fiber samples were prepared; untreated, alkaline treated, acetylated, and a combined alkaline-treated/acetylation samples. The samples were evaluated for their hygroscopic nature, thermal stability, and tensile properties. It is found that acetylation resulted in a reduction of moisture absorption of sisal fiber as the acetylated and alkaline-treated/acetylated samples recorded a decrease of 42% and 28%, respectively. Alkaline treatment increased the absorbency owing to the removal of hemicellulose and lignin. The thermogravimetric result revealed that alkaline treatment improved the thermal stability as the alkali-treated and alkali-treated/acetylated samples showed improvement in thermal properties. The acetylated sample resulted in a significant reduction in tensile strength. But, the results from tensile tests of the alkaline-treated samples showed an insignificant decrease in tensile strength and improvement in the modulus for all treated samples. Fourier-transform infrared and scanning electron microscopic analysis were included in the study to supplement the results with structural and microstructural changes. The effect of those treatments on the sisal–PET composite properties was studied and will be submitted in part 2 of the study.

Characterization of whey protein-based films incorporated with natamycin and nanoemulsion of α-tocopherol

Food packaging materials are commonly derived from petroleum that increases global contamination; this raises the interest to evaluate raw material from renewable sources such as whey protein for the development of packaging materials, especially to produce active films. This research aimed to evaluate whey protein-based film properties when natamycin, nanoemulsioned α-tocopherol, or both were added. An oil-in-water (O/W) nanoemulsion of antioxidant (α-tocopherol) was prepared by microfluidization technique. Four films were prepared with different levels of natamycin and nanoemulsified α-tocopherol and were characterized in terms of physicochemical, mechanical, optical-properties, water vapor barrier, FTIR, microstructure, antioxidant and antimicrobial activity. The natamycin, nanoemulsified α-tocopherol, or both did not modify the moisture content of the films. Moreover lead to a significant reduction of tensile strength and elastic modulus, while presenting growth in the elongation at break. Film opacity, the total color difference, the UV-Vis light barrier, and the water vapor permeability values increased when compounds were incorporated into the film. The microstructure studies showed uniformly distributed porosity throughout the films. The addition of nanoemulsioned α-tocopherol into whey protein-based films provoked antioxidant activity and the addition of natamycin produced films with effectivity against C. albicans, P. chrysogenum, and S. cerevisiae, allowing develop a material appropriate for use as active food packaging.

Microbial degradation of four biodegradable polymers in soil and compost demonstrating polycaprolactone as an ideal compostable plastic

Plastics are an indispensable material but also a major environmental pollutant. In contrast, biodegradable polymers have the potential to be compostable. The biodegradation of four polymers as discs, polycaprolactone (PCL), polyhydroxybutyrate (PHB), polylactic acid (PLA) and poly(1,4 butylene) succinate (PBS) was compared in soil and compost over a period of more than 10 months at 25 °C, 37 °C and 50 °C. Degradation rates varied between the polymers and incubation temperatures but PCL showed the fastest degradation rate under all conditions and was completely degraded when buried in compost and incubated at 50 °C after 91 days. Furthermore, PCL strips showed a significant reduction in tensile strength in just 2 weeks when incubated in compost >45 °C. Various fungal strains growing on the polymer surfaces were identified by sequence analysis. Aspergillus fumigatus was most commonly found at 25 °C and 37 °C, while Thermomyces lanuginosus, which was abundant at 50 °C, was associated with PCL degradation.

On the low-cycle fatigue behavior of friction stir welded Al–Si12 parts produced by selective laser melting

The solid-state friction stir welding (FSW) process was used to join Al–Si12 parts fabricated via the selective laser melting (SLM) technique. The effect of the welding process on microstructural evolution and mechanical properties of the samples is investigated in present work. Microstructural studies demonstrate that FSW is capable of changing Si phase morphologies (i.e. shape and size) resulting in various mechanical properties. The stir zone of the welded joint shows significantly lower micro-hardness in comparison to the as-built SLM samples. Correspondingly, the friction stir welding process results in significant reduction of tensile strength, while ductility is strongly improved. The fully-reversed strain-controlled low-cycle fatigue (LCF) tests imply that at low strain amplitudes the FSW and SLM samples show almost the same fatigue life, while at the high strain amplitudes the SLM samples show superior LCF performance. Fracture analysis of fatigued samples reveals that the near-surface pores lead to the crack initiation in both SLM and FSW cases.

Tensile strength of flax fabrics to be used as reinforcement in cement-based composites: experimental tests under different environmental exposures

The use of Textile-Reinforced-Matrix (TRM) systems is gaining consensus as a possible technical solution for strengthening masonry structures. In this context, the use of natural fabrics (among which those made of flax) instead of synthetic ones can have a positive impact on several sustainability-related aspects, such as renewability, recyclability, biodegradability, low price. However, both mechanical properties and durability performance of natural fibres and fabrics needs to be further investigated with the aim to make it possible their use in composites for construction. Furthermore, this paper reports the results of a fundamental study on a bidirectional flax fabric eventually intended as the reinforcement in cement-based composite systems. Specifically, it aims at determining the tensile strength of flax of fibres, threads and the fabrics, and investigating how they are influenced by various environmental exposures and aging processes. The results in the experimental tests reported herein show that fibres and fabrics suffered no significant reduction in tensile strength due to the considered environmental exposure. Despite the common belief that natural fibres may be affected by durability issues, the results demonstrate that the flax fabric under investigation can be utilised as a reinforcement in TRM systems, which is the main novelty and original contribution of this paper.

Effects of Al and Y Addition on Microstructures and Mechanical Properties of As‐Cast Mg–14Li Based Alloy

In this study, effects of Al and Y contents on microstructural evolutions and mechanical properties of the as‐cast Mg–14Li alloy are investigated. The results show that Mg–14Li–xAl (x = 1, 2, 3 wt%) alloys are characterized by predominantly single β–Li and MgLiAl2 phases. Slight refinement of β–Li grains is obtained with the increasing of Al content. The increased Al addition greatly improves the hardness, ultimate tensile strength, and yield strength of the Mg‐14 base alloy, accompanied by a significant reduction in ductility. Meanwhile, with addition of minor Y (0.5 wt%) addition leads to the introduction of homogeneous distribution of Al2Y particles in the Mg–14Li–3Al alloy, which plays a positive role in the strength enhancement. However, the uneven distribution of apparently coarsed Al2Y particles contributes to a significant reduction in tensile strength as the Y content is increased up to 1 wt%.

Corrosion experiments on IN-RAFM steel in flowing lead-lithium for Indian LLCB TBM

Corrosion experiments were carried out in a pump driven loop, exposing IN-RAFM (India specific Reduced Activation Ferritic Martensitic) steel samples to lead-lithium, Pb-16Li. In this loop, flat and tensile samples, made of IN-RAFM steel were exposed to lead-lithium, flowing at ∼10 cm/s velocity and maintained at (465 ± 3)°C temperature. Three experiments were carried out, for different time durations, 1000 h, 2500 h and 5000 h. Samples were removed after each experiment and metallurgical investigations were carried out using SEM and SEM/EDX. Tensile strength and hardness measurements were also carried out and the results are discussed in this paper. Corrosion rate estimated from weight loss measurements was ∼44 μm/year up to 2500 h and it reduced to ∼31 μm/year after 5000 h exposure. Iron and chromium were found leaching from the samples. Hardness reduction was observed up to 40 μm after exposing to liquid metal for 5000 h. There is no significant reduction in tensile strength and % elongation after exposing the samples up to 5000 h to liquid metal.

Work hardening behaviour in banded dual phase steel structures with improved formability

In this work, we show how the presence of microstructural banding and segregation affects the work-hardening behaviour of a dual phase steel with improved formability. This steel contains chemical segregation inherited from the casting process. Our previously developed 3D cellular automaton model allowed us to design thermo-mechanical processes to either promote or suppress banding. The bands are properly described as in-plane sheets of martensite grains. Mechanical testing data revealed a significant reduction in tensile strength in banded structures for a similar level of ductility. The work-hardening behaviour in the pre-yield regime, including the yield strength itself, is not correlated to the incidence of segregation and/or microstructural banding. The reduction in ultimate tensile strength in banded structures stems from a reduced work-hardening capacity in the post-yield regime. This is due to increased austenite stability in the banded steels, coupled to the anisotropic strain localisation in the ferritic matrix between martensite bands.

Atomistic Origins of Ductility Enhancement in Metal Oxide Coated Silicon Nanowires for Li‐Ion Battery Anodes

AbstractSilicon nanowires (SiNWs) are a promising anode material for Li‐ion batteries due to their exceptionally high charge capacity. However, direct implementation is hindered by large volume expansion induced during lithiation, which results in mechanical failure during repeated charge cycling. Recent experimental works show thin metal oxide coatings can significantly increase the cycle stability of SiNWs. However, the deformation mechanisms underpinning this performance enhancement are not understood, presenting an opportunity for a fundamental investigation of core–shell mechanics. In this study, molecular dynamics simulations investigating the mechanical behavior of silica‐ and alumina‐coated SiNWs under uniaxial tension are performed. Metal oxide coated nanowires possess significantly improved ductility, increasing the elongation to failure from 16% to greater than 47%. This occurs without significant reduction in tensile strength, resulting in apparent toughness 2–4 times that of uncoated nanowires. During loading, the oxide coating absorbs strain energy through breaking of bonds between highly coordinated atoms. At the same time, the coating maintains the structural integrity of the silicon core by increasing the defect nucleation rate from the core‐coating interface, preventing localized deformation. Under both athermal (0 K) and room temperature conditions, the underlying deformation mechanism changes from amorphization within a localized shear band to dislocation twinning and large‐scale amorphization.