Strength Of Glass Research Articles

The Role of Bioactive Glasses in Modern Dentistry: From Remineralization to Regeneration

Aim: This review explores the potential of bioactive glasses in dentistry, focusing on their applications in dental restorations, implants, and tissue regeneration. The aim is to assess the challenges and opportunities in their use, as well as the future directions for enhancing their performance. Materials and Methods: A comprehensive review of recent literature was conducted to analyze the properties, applications, and limitations of bioactive glasses in dental materials. Studies on the composition, mechanical properties, biocompatibility, and long-term in vivo performance were included. Methods to enhance the mechanical strength of bioactive glasses, such as the formation of composites and advanced nano structuring, were also explored. Results: Bioactive glasses have shown great promise in promoting remineralization, supporting tissue regeneration, and bonding with hard tissues. However, challenges such as mechanical brittleness, high costs, and limited long-term stability have been identified. Research on enhancing mechanical strength through composites, as well as developing more cost-effective production methods, is ongoing. Conclusion: Bioactive glasses offer significant potential for improving dental treatments and advancing regenerative medicine. Future research should focus on enhancing their mechanical properties, developing personalized bioactive materials, and exploring their integration with stem cell therapies and growth factors. With continued development, bioactive glasses could revolutionize dental restorations, implants, and oral tissue regeneration, providing innovative solutions for oral healthcare.

Bond Performance of GFRP Bars in Glass and Basalt Fiber-Reinforced Geopolymer Concrete Under Hinged Beam Tests

In recent years, researchers have focused on the usability of fiber-reinforced polymer (FRP) bars due to their lightweight, corrosion-resistant, and eco-friendly characteristics. Geopolymers, as low-carbon alternatives to traditional binders, aim to reduce CO2 emissions in concrete production. The bond strength between FRP bars and concrete is critical for the load-bearing capacity and deformation characteristics of reinforced elements. The objectives of this work are to investigate the bond performance of GFRP bars in chopped glass and basalt fiber-added geopolymer concrete using hinged beam tests. Since the hinged beam test accurately represents the behavior of real bending elements, this test method was selected as a main bonding test. Initially, three geopolymer mixtures with Ms modulus values of 1.2, 1.3, and 1.4 were prepared and tested. The mixture with a modulus of 1.2 Ms, achieving a compressive strength of 56.53 MPa, a flexural strength of 3.54 MPa, and a flow diameter of 57 cm, was chosen for beam production due to its optimal workability and strength. After mechanical and workability tests, SEM analysis was performed to evaluate its internal structure. For evaluating the bond performance of GFRP bars, 12 geopolymer beam specimens were prepared, incorporating varying fiber types (chopped glass fiber or basalt fiber) and embedment lengths (5 Ø or 20 Ø). Hinged beam tests revealed that the bond strengths of glass and basalt fiber-added mixtures were up to 49% and 37% higher than that of the control geopolymer concrete, respectively. It was concluded that incorporating fibers positively influenced the bond between geopolymer concrete and GFRP bars, with glass fibers proving more effective than basalt fibers. These findings enhance the understanding of bond mechanisms between GFRP bars and geopolymer concrete, emphasizing their potential for sustainable and durable construction in both industrial and scientific applications.

Glass fiber treated with a glycine bridged silane coupling agent reinforcing polyamide 6(PA6): effect of hydrogen bonding.

Silane coupling agents play an indispensable role in improving interfacial adhesion of composite materials, but their interaction mechanism is often unclear. This article combines experiments and theoretical calculations to reveal the importance of hydrogen bonds between silane coupling agents and the matrix polyamide 6 in improving the mechanical properties of composite materials. Firstly, glycine bridged silane (GBSilane) was synthesized and the structure was confirmed by FT-IR, 1H NMR and HRMS. Secondly, with glass fiber treated using GBSilane as a filler, the mechanical properties of glass fiber/PA6 composite materials were studied. Compared with untreated glass fiber/PA6 composites, under the optimal treatment concentration of 1.5%, the tensile strength of glass fiber/PA6 composites treated with 3-aminopropyl triethoxysilane (APTES) and GBSilane increased by 41% and 67%, respectively, and the notch impact strength increased by 55% and 96.5%, respectively. Lastly, density functional theory (DFT) calculations revealed that stronger hydrogen bonds have formed between GBSilane and PA6 than APTES, which have induced the stronger PA6-GBSilane binding energy of 58.20 kJ mol-1. By comparison, the binding energy of PA6-APTES is only 30.91 kJ mol-1. These results demonstrated that the as-synthesized GBSilane could improve the mechanical properties of PA6 composites through an enhanced hydrogen bonding mechanism.

Preparation of glass-ceramics via co-sintering of coal fly ash and metastable slag

ABSTRACT Coal fly ash (CFA) was used as the main object of study to prepare ash microcrystalline glass by co-sintering with metastable slag (MS) using its strong crystallization ability and sintering activity at low and medium temperatures. The effects of different material ratios on the crystalline phase composition and properties of the microcrystalline glass were discussed using various physical and chemical analysis methods in combination with mechanical properties tests. The results show that the compressive strength, density, chemical resistance and sintering densities of ash microcrystalline glass gradually increase with the increase of sintering temperature and the proportion of metastable slag. The compressive strength of the prepared ash microcrystalline glass can meet the requirements of GB/T19766–2016 “Natural Marble Building Panel” (≥50 MPa) when the addition amount of fly ash is 10–40% and the sintering temperature is 850–1085°C; among them, the chemical corrosion resistance of the prepared product meets the industrial requirements when the addition amount of fly ash is 10–30% and the sintering temperature is 940°C (acid loss rate ≤ 96%, alkali loss rate ≤ 98%).

Mechanical Behavior of Ion-Exchanged Alkali Aluminosilicate Glass Ceramics

Glass is one of the oldest and most versatile manmade materials and has been used for centuries. One of the areas of significant research and progress is that of high-mechanical-resistance glass. Several processes can be used to maximize the mechanical strength of glasses, namely thermal or chemical treatments. Glass ceramics, obtained through controlled crystallization, can enhance the mechanical properties of these materials and, as long as the crystals remain small enough, transparent glass ceramics can be obtained. On the other hand, ion exchange can strengthen the glass surface and reduce failure. As a result, ceramization followed by ion exchange can further enhance the mechanical characteristics of the parent glass. Aluminosilicate glasses and glass ceramics are known to present excellent transparency and chemical durability, plus good mechanical behavior; therefore, a lithium aluminosilicate glass composition was studied in order to obtain transparent glass ceramics, followed by an ion exchange process, and its mechanical properties were studied. Transparent glass ceramics were obtained, with an increase of ~15% in hardness over the parent glass. The glass ceramics were then subjected to an ion exchange treatment in a KNO3 bath, in order to further enhance the mechanical properties, without hindering the optical transmittance. The combination of heat treatment and chemical treatment resulted in a cumulative hardness increase of ~25%, from 620 ± 10 HV, for the as-cast glass and from 773 ± 23 HV for the ion-exchanged glass ceramic. Regarding the indentation fracture toughness, values obtained for the glass ceramics were similar to those obtained for the cast glass, yielding no noticeable change. Indentation fracture toughness increased after the ion exchange treatment of the glass ceramic, since a much higher load was necessary to obtain a measurable indentation, indicating higher indentation fracture strength.

ТЕОРЕТИЧЕСКИЕ И ТЕХНОЛОГИЧЕСКИЕ ОСНОВЫ ПРОЦЕССОВ ФОРМИРОВАНИЯ МИКРОСТРУКТУРЫ ПЕНОСТЕКЛА С ИСПОЛЬЗОВАНИЕМ ВТОРИЧНОГО МИНЕРАЛЬНОГО СЫРЬЯ

Increasing the strength of foam glass to values sufficient for using it not only as a heat-insulating but also a structural material will significantly expand the scope of its application and reduce the material intensity of construction. The solution is possible due to the formation of a controlled and predictable heterogeneous amorphous-crystalline structure. The effect of the crystalline phase on the structure and strength of foam glass is contradictory and requires significant attention. At the same time, it is necessary to take into account the already obtained research results on reducing the cost of the material due to the use of waste. However, the composition of waste from various landfills varies, so a universal methodology for the development of materials is needed. A unified methodology is proposed that allows solving the problem of designing new materials using waste of various compositions, special attention is paid to the problem of synthesizing the composition of the initial batch and the temperature-time mode of foam glass synthesis. To confirm the proposed methodology, the material was developed using the example of ash and slag mixture of the TPP in Novocherkassk. The obtained foam glass samples and the research results were used to establish the features of the processes of formation of the foam glass microstructure using the regression analysis method.

On the dynamic failure mechanism of Vit-1 bulk metallic glass: Coupling effects of pre-made damage and strain rate

To clarify the two distinct effects and the underlying physical mechanisms of pre-made damage on the failure strength of bulk metallic glass (BMG), i.e. strengthening or weakening, the influence of axial pre-compression on the dynamic failure of Vit-1 BMG are investigated experimentally. Quasi-static and dynamic compression tests were conducted on pre-compressed BMG specimens for a wide range of nominal strain rates between 0.001 s−1 to 6000 s−1. The focus is on the coupled effects of pre-compression and strain rate on the dynamic failure stress. Two contrasting mechanisms were identified that influence how the pre-made shear bands affect the propagation of cracks under different strain rates. It will be shown that the dynamic failure stress exhibits a transition from strengthening to knockdown with increasing strain rate; and, that the extent of these strengthening and knockdown effects depends on the pre-compression strain level. Finally, a failure model that captures the effects of both strain rate and pre-made damage is proposed.

Structural, physical, and Judd-Ofelt analysis of germanium magnesium-telluroborate glass containing different amounts of Tm2O3

Germanium magnesium-telluroborate glasses with the composition 78B2O3–10GeO2–5TeO2–(7−x) MgO–x Tm2O3, x = 0, 0.25, 0.5, 1, and 1.5 mol% were fabricated by using the melt quenching process. With the increase of Tm2O3 concentration, the density values increase from 3.574 to 4.153 g/cm3, while the molar volume values decrease from 21.145 to 19.445 cm3/mol. Fourier transform infrared analysis supports the existence and conversion of BO3 and BO4. The conversion of BO3 to BO4 would lead to greater bridging oxygens (BOs), influencing and reinforcing the glass network. The optical features were studied as well. The optical band gap decreased by increasing Tm2O3 content in the glass formula, while the index of refraction increased. The parameters take the values between 3.16 eV and 2.31 eV. Other optical and physical constants were determined like optical conductivity, electronegativity, metallization, reflection loss, steepness parameters, and transmission coefficient. Judd-Ofelt theory is used to estimate the optical intensities and line strengths of the present glasses. Radiative lifetimes and branching ratios are evaluated of different manifolds belonging to Tm3+ doped present glasses. The results showed the possibility of potential applications for these materials in the fields of laser development, light-emitting diodes (LEDs), optical amplification and optoelectronic devices.

Constructing ZSM-5 loaded with 2-mercaptobenzimidazole on glass fiber for enhancing the anti-corrosion and erosion resistance properties of epoxy coating

Glass fiber reinforced polymer coatings (GFRPC) are used to protect steel structures in harsh marine environments due to high mechanical strength and chemical stability. The composite coating not only suffers from impact damage by seawater and sediment but also experiences corrosion damage in the splash zone. However, the GF has weak interfacial adhesion with polymer resins due to the chemical inertia and smooth surface, which limits the service lifespan of GFPRC. Hence, ZSM-5 zeolite were in situ prepared on the surface of glass fibers by hydrothermal synthesis, and 2-mercaptobenzimidazole (MBI) was further adsorbed to obtain difunctional hybrid glass fibers (ZGFM) to enhance the interfacial adhesion strength of glass fiber/resin and also the erosion resistance and anti-corrosion ability of composite coatings. Compared to GF/EP, the interfacial shear strength of ZGFM/EP was increased by 104.39 %. After immersion under an alternating hydrostatic pressure of 20 MPa for 12 days, the impedance value of the ZGFM/EP composite coating remained at 6.40 × 109 Ω•cm2, demonstrating outstanding deep-sea anti-corrosion performance. Following the erosion test, the ZGFM/EP exhibited a reduction in mass loss and volume loss by 10.65 % and 12.55 %, respectively, in comparison to the pure EP coating. The excellent interfacial strength between ZGFM and EP ensured effective stress transfer, which prevented crack propagation, thus enhancing the mechanical properties and erosion resistance of the composite coating. Meanwhile, electrochemical experiment proves glass fiber with MBI loaded obviously inhibits the corrosion reaction.

Impact of ZnO content in BAS glass–ceramics and pre‐oxidation temperature on Kovar alloys to their sealing strength

AbstractThis work studied the effect of Si/Zn ratio on the structure of B2O3–Al2O3–SiO2 (BAS) parent glass and the microstructure, properties of the resulting glass‐ceramics after heat treatment. Additionally, the effects of different pre‐oxidation temperature of Kovar alloys and sealing temperature on the shear strength of these sealed glass–ceramics‐to‐Kovar samples were studied. First, the parent glass precipitated three kinds of crystals Al0.52Zr0.48O1.74 (PDF#53‐0294), ZrO2 (PDF#37‐1484), and ZnAl2O4 (PDF#05‐0669) in BAS glass–ceramics. The coefficient of thermal expansion of glass–ceramics increased from 48.17 × 10−7 to 54.92 × 10−7°C−1 with the gradual increase of ZnO content. With an optimizing pre‐oxidized temperature of Kovar at 950°C, a champion sample with the highest sealing strength of 6.086 MPa was achieved when BAS glass–ceramics sealed to Kovar at 1000°C for 30 min. Moreover, the sealing interface was observed to consist of four distinct regions: the matrix alloy, the alloy iron‐deficiency area, the iron‐rich glass–ceramics, and the matrix glass–ceramics.

Nanoporous Structure Fabrication on Glass Surfaces for Enhanced Glass Adhesion Using Hydrogen Fluoride Gas.

The bonding between glass and other materials plays a crucial role when glass is used in industrial products. In this study, we propose a new approach to enhance the bonding strength of glass with other materials by fabricating nanoscale porous structures on glass surfaces via a chemical reaction with hydrogen fluoride gas. Herein, we present a methodology for controlling the thickness of the porous structure, clarify the relationship between the thickness and adhesion strength, investigate the shape of the formed porous structure, and propose a method to control its shape. Our findings reveal that the fabricated porous structure greatly improves the adhesion strength of the adhesive owing to the microscopic anchoring effect induced by the penetration of the adhesive into the porous structure. This approach is expected to be applied to architectural and automobile window glasses, solar panels, sensor cover glasses of autonomous vehicles, display devices (including smartphones), and wearable devices.

Properties of foam glass produced with the use of soot from a cement factory as a foaming agent: A study based on Taguchi design of experiments

Cellular glass is a lightweight, porous medium with excellent heat transfer resistance that can be used in a variety of industries. This study investigated the use of soot from cement plants as a new foaming agent for producing foam glass. The experiments were designed using the Taguchi Design of Experiments (DOE) method. By applying this approach, instead of creating and testing 27 different groups of samples, only 9 groups were produced. The properties of the remaining 18 sample groups were then predicted based on Taguchi analysis. Soot and silicon carbide were used simultaneously (at weight ratios of 2 % and 3 %) as foaming agents in the samples. Alumina was also used as a modifier with weight ratios of 4 %, and 8 %. Mechanical strength, water absorption, density, and thermal resistance were evaluated. The findings indicated a direct correlation between elevated soot content and increased water absorption (open porosity), coupled with a reduction in compressive strength and overall density of the foam glass. Electron microscopy observations revealed a wide range of crystallite morphologies in the resulting foam glass, which results in diverse properties in the material. The developed glass foams exhibit a density spanning from 125 to 700 kg/m3, with compressive strength varying between 1.2 and 6.7 MPa, and thermal conductivity in the range of 0.08–0.5 W/m·K. The samples with 3 % soot, 0 % alumina, and 3 % SiC exhibited exceptional thermal insulation properties. In contrast, the samples containing 1 % soot, 8 % alumina, and 1 % SiC demonstrated the highest compressive strength. Overall, this study found that soot from cement plants is a viable foaming agent for producing foam glass with desirable properties. The use of soot from cement plants can not only reduce the dispersion of pollution in the environment but also produce a wide range of foam glass with different properties at a lower cost.

Numerical simulation of anti-shatter films (ASF) for mechanical post-breakage analysis of retrofitted glass

Post-breakage strength and residual mechanical capacity improvements are important tasks for load-bearing structural components in general, and even more for glass elements, in order to protect people from injury in case of breakage. For this reason, among others, the design of glass components and structures is based on key concepts that are generally summarized in structural safety, robustness and redundancy. With regard to the last fundamental requirement, nowadays the use of laminated glass (LG) sections is spread for many applications and new projects, such as automotive or aircraft windshields, but especially curtain walls and many other load-bearing applications in buildings. This strategy derives from the intrinsic safety and security levels of LG sections after possible glass breakage. When LGs are not available (i.e., existing components), anti-shatter safety films (ASF) for the retrofit of monolithic glass elements are expected to provide very similar post-breakage structural performances against bending and impact actions, by reducing the possible spread of glass shards. Besides, the residual load-bearing capacity of glass components retrofitted by ASF is still challenging to quantify. In this paper, the Cohesive Zone Model (CZM) theory is considered to investigate, with the support of experiments and Finite Element (FE) numerical models, the performance of small-scale monolithic glass specimens retrofitted by ASF under bending loads. Different ageing procedures and imposed displacement-rates are considered to evaluate the influence of basic operational parameters, such as temperature and humidity, on the mechanical efficiency of common ASF layers. In doing so, the sensitivity of fundamental input parameters (i.e., maximum tensile strength of glass and fracture energy of the ASF adhesive) on the mechanical performance at pre- and post-breakage stages of retrofitted monolithic glass elements is explored.

A Low-Hydroxyl Quartz Glass Prepared by Using a Plasma Heat Source as the Flame and High-Purity Quartz Sand as the Raw Material

In this paper, a quartz glass with low hydroxyl groups was prepared by combining the advantages of various processes, using a plasma heat source as the flame and high-purity quartz sand as the raw material. The purity of the quartz sand was 99.997%. The number of air bubbles in the quartz glass prepared using high-purity quartz sand was lower. The hardness and tensile strength of the quartz glass were 737.7–767.1 GPa and 6.88–9.64 MPa, respectively. The hydroxyl content of the sample was only 4.11 ppm, and the hydroxyl content of the homogenized quartz glass was reduced to 2.64 ppm, which was an improvement of about 35%. After homogenization, the fictive temperature (Tf) of the quartz glass was determined to be 1253 cm−1, and the variation of the Tf value along the radial direction was reduced, indicating a more homogeneous glass structure. The stress distribution in the quartz glass was significantly improved. These results indicate that the preparation of quartz glass from high-purity quartz sand using a plasma heat source as the flame opens up new avenues for optical applications.

Influence of Dentin Sealing Technique on the Shear Bond Strength between Lithium Disilicate Ceramics and Try-In-Paste-Contaminated Dentin

This study aimed to evaluate the effect of try-in paste contamination on the bond strength of lithium disilicate glass–ceramic to dentin treated with immediate (IDS) or delayed (DDS) dentin sealing techniques. Occlusal halves of 33 molars were decapitated and divided into three groups (n = 10). Lithium disilicate discs (3 × 5 mm) were prepared. For Group A, the provisional crown was applied over dentin and was soaked in distilled water. Lithium disilicate discs were cemented following dentin conditioning with a three-step etch and rinse adhesive. In Group B (IDS), the three-step adhesive was applied to dentin. The dentin surfaces were conditioned only in the final cementation for Group C (DDS). The intaglio surfaces of test groups were contaminated with try-in paste. All specimens were thermally cycled 3000 times at 5–55 °C and were subjected to shear tests. An additional three specimens for each group were contaminated with try-in paste and subjected to the same surface cleaning as the test specimens were examined with SEM/EDS. The adhesive surfaces were also examined with SEM/EDS for try-in paste remnants. Group C showed a significant decrease in bond strength values compared to Group B and Group A (5.84 ±1.4 MPa, 11.45 ±2.4 MPa, and 10.29 ±2.5 MPa, respectively). No statistically significant difference was detected between Group B and Group A (p ≥ 0.05). The SEM-EDS analyses revealed obstructions of the dentinal tubules in the try-in-paste-contaminated specimens. Immediate dentin sealing application enhanced the bonding strength of lithium disilicate to the try-in-paste-contaminated dentin. Try-in paste contamination over dentin negatively influenced the bonding process.

Shear strength and optical bandgap in As2Se3 glasses permanently compacted under GPa pressures

The application of GPa pressures on glassy As2Se3, at temperatures just below and above its glass transition, leads to permanently compacted glasses that exhibit increased densification. Also, melt-quenching of the same glass under a pressure of 7 GPa gives rise to the formation of its crystalline β-phase. The structure of these As2Se3 compacted solids have been explored by X-ray diffraction. Measurements of 10 MHz ultrasound velocities reveal that the density increase is associated with a substantial hardening of the elastic continuum as well as a growing shear strength of glassy solids: the shear modulus G increases by more than 35 % and the Poisson's ratio ν decreases by more than 13 %. The optical properties have been investigated by UV–VIS diffuse reflectance spectroscopy, which shows a well defined linear reduction of the optical bandgap Eg with increased density. All of these observations have been explained by considering a disordered layered structure of glassy As2Se3, where densification produced by compaction under GPa pressures gives rise to a progressive strengthening of the interlayer interactions.

Evaluation of crack initiation load of silica glass surfaces formed during subcritical crack growth

AbstractThe crack initiation load of freshly fractured surfaces for silica glass was evaluated with ball indentation. The fracture surfaces were formed during subcritical crack growth in the regions I, II, and III of the stress intensity factor (KI)—crack velocity (V) curve. From the KI–V curve, we linked the obtained fracture surfaces with the ones in the regions I, II, and III. It was found that the crack‐forming probability was the lowest for the fracture surface formed in the region III of the KI–V curve. In order to understand the controlling factors of the crack formation, some properties which are topography, relative nonbridging oxygens (NBO), hydrogen concentrations, and Si–O three‐ or four‐membered ring structures, of the fracture surfaces were measured by atomic force microscopy, X‐ray photoelectron spectroscopy, dynamic secondary ion mass spectroscopy, and Raman spectroscopy, respectively. No distinct difference in NBO and hydrogen concentrations nor the ring structures were found among the fracture surfaces formed in different regions in the KI–V curve. The peak‐to‐valley height of the fracture surface, however, decreased with increasing crack velocity. It is concluded that the roughness or topography of the freshly fractured surface is one of the controlling factors which reduce the intrinsic strength of silica glass.

Densification and network structural changes in binary aluminosilicate glass via cold sintering process

Binary aluminosilicate glasses containing 20–50 wt% Al2O3 were successfully densified through a cold sintering process (CSP) using 1–10 M NaOH solutions. The investigation focused on densification and structural unit changes in the cold-sintered binary aluminosilicate glasses. Specifically, the binary aluminosilicate glass with 40 wt% Al2O3, cold-sintered at 180 °C using 1–10 M NaOH solutions, achieved a relative density of up to 90 % at 10 M NaOH. This was attributed to an enhanced dissolution-precipitation process facilitated by an increased concentration of the NaOH solution. In aluminosilicate glasses with 20–50 wt% Al2O3, the relative densities approached 90 % after CSP at 180 °C using a 10 M NaOH solution. Al(OH)3 formation in the cold-sintered glasses was confirmed, particularly at higher concentrations of NaOH solution (>10 M) and higher contents of Al2O3 (>40 wt%). Changes in Si structural units were observed during CSP, with Al-rich Si units becoming dominant as the concentration of the NaOH solution increased. The higher substitution of Si-O-Si bonds by Si-O-Al bonds led to the precipitation of Al(OH)3, as well as an increased Vickers hardness and biaxial flexural strength of the cold-sintered glasses. These findings demonstrate that the Al2O3 content and NaOH concentration play important roles in the densification and enhancement of the mechanical property in the cold-sintered alumina-rich binary aluminosilicate glasses and offer insights into the optimal conditions for obtaining desirable aluminosilicate materials through CSP.

The Impact of Welding Parameters on the Welding Strength of High Borosilicate Glass and Aluminum Alloy

This study adopts a new surface pretreatment method, Laser Surface Remelting (LSR). This experiment aims to establish a set of laser welding process parameters suitable for aluminum alloy and glass under this specific pretreatment. This experiment explores the impact of laser welding parameters on the welding strength between high borosilicate glass and aluminum alloy. The study specifically investigates the effects of four process parameters: defocus amount, laser power, frequency, and pulse width on the welding outcome. The results indicate that the welding quality between the aluminum alloy and glass reaches its optimum when the defocus amount is zero (i.e., when the laser converges at the interface between the glass and the metal) and the laser welding parameters are set to a power of 250 W, a welding speed of 1 mm/s, a welding frequency of 10 Hz, and a pulse width of 2.5 ms. The experiment also analyzes the fracture morphology under different parameters, summarizing the locations and causes of fractures, and establishing the relationship between the fracture location and the welding strength.

Strengthening effects of indentation notches on metallic glasses and their sensitivity to stress triaxiality

In this study, a metallic glass sample with an annular indentation notch was successfully constructed by a compression rod cyclic compression strategy using molecular dynamics simulation, and the mechanical behaviors of cut-notched metallic glass samples with the same stress triaxiality and notch size under triaxial compression were comparatively analyzed. It is found that the indentation notch further improves the strength and plasticity of the metallic glass, while it is insensitive to the cut-notched metallic glass with the same notch size. During triaxial compression, rejuvenation and shear softening lead to an increase in free volume, while diffusion and residual compressive stresses lead to a decrease in free volume. The stress triaxiality plays a key regulatory role in their competition and affects the final state of free volume change. This study provides a new theoretical basis and process idea for the enhancement of strength and plasticity of metallic glass.