The Coupling between Voltage Profiles and Mechanical Deformations in LAGP Solid Electrolyte During Li Plating and Stripping

Chemo-mechanical degradation at the solid electrolyte – Li metal electrode interface is a bottleneck to improve cycle life of all-solid state Li-metal batteries. In this study, in operando digital image correlation (DIC) measurements provided temporal and spatial resolution of the chemo-mechanical deformations in LAGP solid electrolyte during the symmetrical cell cycling. The increase in strains in the interphase layer was correlated with the overpotential. The sudden increase in strains coincides with the mechanical fracture in LAGP detected by Micro CT. This work highlights the mechanical deformations in LAGP / Li interface and its coupling with the electrochemical behavior of the battery.

Ударное разрушение кристаллического, аморфизованного имплантацией Ar-=SUP=-+-=/SUP=- и аморфного диоксида кремния

The mechanical fracture of silicon dioxide initiates the mechanoluminescence (ML) lighting due to multiple breakage of interatomic bonds with producing non-bridged oxygen groups of [Si–O–]. The detected ML signals consisted of series of pulses, the energy of which is proportional to the number of photons irradiated from the broken bonds. The comparative analysis of the energy distributions in ML series induced by the impact damage of the surface of crystalline and vitreous SiO2 before and after the Ar+-ion implantation was conducted. The interplay between random and correlated accumulation of broken bonds under the impact loading was found and discussed.

Regularities of Stress-Corrosion Cracking of Pipe Steel 09G2S at Cathodic Polarization in a Model Soil Environment

Peculiarities of corrosion-mechanical fracture of 09G2S pipe steel samples in the conditions of cathodic protection were investigated. It was established that depending on the level of protective potential, stress-corrosion cracking of pipe steel of a ferrite-pearlite class 09G2S can occur by different mechanisms. The range of protective potentials was determined, at which the anodic dissolution and hydrogen embrittlement occur simultaneously during the fracture of steel, namely from -0.85 V to -1.0 V. The existence of the above mechanisms is confirmed by the change in the strength and viscosity properties of the steel and the morphology of the fractures. For steels of other manufacturing technology and grades, these potential areas may differ.

Mechanical fracture parameters of concrete drill-core specimens supported by a slenderness ratio study

The detailed analytical and experimental investigation of the fracture behaviour of quasi-brittle materials is an endeavour which has been ongoing worldwide for many years. Such materials are usually characterized in terms of their mechanical fracture parameters, which are determined based on the evaluation of quasi-static fracture experiments. One of the most commonly used building materials with a quasi-brittle response is concrete, which is most often based on a cement matrix. It is sometimes also necessary to characterize concrete included in existing structures. In this case, test specimens are obtained by core drilling, and the investigation is conducted with the requirement to maximize the number of parameters obtained while minimizing the number of test specimens drilled from the structure. This paper focuses on the mechanical fracture parameters of core-drilled specimens taken from a selected concrete structure. Tests were performed on cylindrical specimens with a chevron-notched stress concentrator in the three-point bending configuration in order to determine modulus of elasticity, fracture toughness and fracture energy. Subsequently, theoretical compressive strength was estimated and tests for the determination of compressive strength values were performed focusing on dependence on the slenderness ratio, i.e. the relationship between the compressive strength and the length to diameter ratio of the cylindrical specimens. In relation to the obtained mechanical fracture parameters, selected specimens were analysed and three-dimensionally characterized via high-resolution X-ray computed tomography.

Optimizing Bladder Resin Transfer Molding Process to Manufacture Complex, Thin-Ply Thermoplastic Tubular Composite Structures: An Experimental Case Study

The bladder molding process is primarily used in sporting applications but mostly with prepregs. Bladder-Assisted Resin Transfer Molding (B-RTM) presents the tremendous potential to automate and mass produce the complex hollow-composite profiles. Thin-ply, non-crimp fabrics (NCFs) provide excellent mechanical, fracture toughness, and vibration damping properties on top of the weight saving it offers to a final product. However, these fiber architectures are difficult to inject due to the resistance they provide for the polymer flow using the liquid injection process. Therefore, it is mandatory to optimize the process parameters to reduce the time for injection and simultaneously achieve better consolidation. This work presents a first, detailed, experimental case study to successfully inject a low-permeability, thin-ply, complex, thermoplastic tubular structure, and the effect of process parameters, boundary conditions, the associated manufacturing challenges, and proposed solutions are deliberated in this paper.

Mechanical, Fracture, and Microstructural Assessment of Carbon-Fiber-Reinforced Geopolymer Composites Containing Na2O

For a sustainable environment, geopolymer (GPO) paste can be used in the construction industry instead of Portland cement. Nowadays, sustainable construction and high-efficacy composites are demanding. Therefore, in the present investigation, the mechanical and microstructural efficacy of carbon-fiber-reinforced fly ash-based GPO with different percentages of nano-sodium dioxide (NS) were studied. The investigated percentages of NS were 0%, 1%, 2%, 3%, and 4%. For all the samples, the carbon fiber content was kept the same at 0.5% by weight. Different percentages of NS for all five fabricated GPO composite pastes were assessed with scanning electron microscopy (SEM). Various mechanical parameters of GPO—the compressive strength, toughness modulus, hardness, toughness indices, impact strength, fracture toughness, flexural strength, and elastic modulus—were evaluated. The results revealed that the use of 3% NS was the most effective for ameliorating the mechanical, microstructural, and fracture behavior of GPO. The use of 3% NS in carbon-fiber-reinforced GPO paste showed the maximum improvements of 22%, 46%, 30%, 40%, 14%, 38.4%, 50.2%, 31%, and 64% for the compressive strength, flexural strength, elastic modulus, toughness modulus, hardness, compressive stiffness, bending stiffness, fracture toughness, and impact strength, respectively. The SEM study showed that the inclusion of NS improved the microstructure and delivered a denser GPO paste by improving the interfacial zones and quickening the polymerization reaction.

Fracture parameters of fly ash geopolymer mortars with carbon black and graphite filler

In this study, the effect of carbon black and graphite filler on the crack initiation and fracture parameters of fly ash geopolymer mortar is investigated. The carbon black was added in the amount of 0.5 and 1.0% and graphite powder in the amount of 5 and 10% relative to the fly ash mass. The reference mixture without any filler was also prepared. The fracture characteristics were determined based on the results of the three-point bending test of prismatic specimens provided with an initial central edge notch. The fracture experiments were conducted at the age of 48 days. The vertical force (F), the displacement measured in the middle of the span length (d), and the crack mouth opening displacement (CMOD) were continuously recorded during the test. The records of fracture tests were subsequently evaluated using the effective crack model, work-of-fracture method, and double-K fracture model. The addition of both fine fillers led to a decrease in monitored mechanical fracture parameters in comparison with reference mortar.