Damage Resistant Materials Research Articles

Effect of pre-deformation on hydrogen diffusion and hydrogen induced damage in commercially pure titanium

This work aims to elucidate the interaction between hydrogen atoms and pre-introduced dislocations in commercially pure titanium (CP-Ti). Positron annihilation spectroscopy supplemented by the first-principle calculations was utilized to reveal the effects of dislocation densities on the formation of hydride types and the concentration of hydrogen-induced defects in CP-Ti. Results show that, in the hydrogen-charged sample with 40 % deformation, hydrogen-induced damage gradually decreases when the hydrogen enters the sample at a depth of about 350 nm. This finding suggests that the high-density dislocations present in deformed specimens effectively trap hydrogen atoms and inhibit their diffusion, which ultimately mitigate damage within the samples. γ-TiH and δ-TiH2 hydrides are observed in the hydrogen-charged sample. The thermal desorption spectroscopy results show that the desorption amount of deuterium decreases from 1.14 × 1018 D/cm2 to 5.10 × 1017 D/cm2 with an increase in dislocation density because dislocations inhibit the diffusion of deuterium. In samples with higher deformation, the high dislocation density inhibits the formation of δ-TiH2 hydrides and promotes the formation of γ-TiH hydrides, which significantly reduce the hardening of samples. These results provide insight into the interaction of hydrogen with pre-introduced defects and provide strong theoretical support for the development and improvement of more damage-resistant materials.

Fretting wear resistance of amorphous/amorphous (AlCrFeNi)N/TiN high entropy nitride nanolaminates

The application of amorphous high entropy ceramics as wear-resistant materials is limited due to their inherent brittleness at room temperature and strain softening during deformation. In order to overcome this limitation, we constructed amorphous/amorphous (AlCrFeNi)N/TiN nanolaminates with varying modulation period thickness by introducing a second amorphous phase through reactive radio frequency (RF) magnetron sputtering, along with corresponding monolithic amorphous films. Microstructure, mechanical properties, and tribological behaviors of the films were characterized wear in detail. Fretting wear results show that the nanolaminates with an average modulation period of 6 nm exhibited a wear rate of 2.8 times lower than that of the (AlCrFeNi)N film and 8.4 times lower than that of the TiN film. Further analysis using FIB-TEM revealed that the enhanced wear resistance of (AlCrFeNi)N/TiN nanolaminates was attributed to the high-density heterointerfaces. These interfaces inhibited the initiation and propagation of mature shear bands and acted as barriers to stress distribution. Additionally, the oxide composite layer at the interface demonstrated a synergistic effect through a mechanically induced tribo-chemical reaction, resulting in slight plastic deformation. For the amorphous (AlCrFeNi)N film, moderate wear resistance was achieved through the formation of transfer layer at the interface. For the amorphous TiN film, the dimensional stability of the film deteriorates due to the significant strain softening that occurs during deformation. This study deepens our understanding of the friction mechanisms involved in amorphous high entropy ceramics, offering valuable insights for the design of high damage-resistant materials.

In situ measurement of damage evolution in shocked magnesium as a function of microstructure

Accurate modeling and prediction of damage induced by dynamic loading in materials have long proved to be a difficult task. Examination of postmortem recovered samples cannot capture the time-dependent evolution of void nucleation and growth, and attempts at analytical models are hindered by the necessity to make simplifying assumptions, because of the lack of high-resolution, in situ, time-resolved experimental data. We use absorption contrast imaging to directly image the time evolution of spall damage in metals at ∼1.6-μm spatial resolution. We observe a dependence of void distribution and size on time and microstructure. The insights gained from these data can be used to validate and improve dynamic damage prediction models, which have the potential to lead to the design of superior damage-resistant materials.

Development of PEG-grafted-lignosulfonate/cationic-polyelectrolyte/poly(acrylic acid) complex and evaluation of its toughness, self-healing property, and internal physical structure

A lignosulfonate-derived material was prepared by complexing polyethylene glycol (PEG)-grafted lignosulfonate (LS-g-PEG) with a cationic polyelectrolyte (PDADMACl). The mechanical property of this LS-g-PEG/PDADMACl complex was similar to those of the conventional unmodified-LS/PDADMACl complex, however, the addition of poly(acrylic acid) (PAAc) improved the toughness of the LS-g-PEG complex more than seven-fold at the optimal composition (from 0.7 to 5.2 MJ/m3). This increase in toughness upon PAAc addition was not observed in the conventional unmodified-LS/PDADMACl complex and it was attributed to the synergistic effect of plasticization by the amorphous PEG component, as well as the formation of a rigid polyelectrolyte complex. In addition to better strain and toughness than other reported lignosulfonate-derived materials, the LS-g-PEG/PDADMACl/PAAc complex displayed a humidity-induced self-healing property; complete healing of mechanical properties was observed under optimal conditions. These good toughness and excellent self-healing properties may broaden the applications of lignin-derived materials as highly durable and damage-resistant materials.

Experimental study for the effect of hole notched in fracture mechanics of GLARE and GFRP composites subjected to quasi-static loading

The requirements for the use of lightweight structures, damage-resistant materials, and optimal fuel consumption in various industries such as aerospace, marine, and automotive structures have increased the need for designing new structural systems to meet these demands. According to research, Fiber Metal Laminates (FMLs) are excellent candidates to meet the above needs. In this study, the tensile test specimens were fabricated according to ASTM D 3039 standard from plain textured glass fibers, aluminum sheet Al 6061-T6 with a thickness of 0.5 mm, and epoxy resin with lay-up of [AL/(GFRP [0,90]4)/Al/(GFRP [0,90]4)/Al]. Glass Fiber Reinforced Plastic (GFRP) specimens were also constructed using E-GLASS fibers with [0,90]20 lay-up. GLARE and GFRP specimens were subjected to tensile testing in two types of simple and open-hole at ambient temperature at the loading rate of 2 mm/min. Failure modes of the simple specimens were studied with open-hole specimens. The failure mechanism in simple glass laminate aluminum reinforced epoxy (GLARE) was delamination, however, in open-hole GLARE, no delamination occurred except for some areas around the hole, and the specimen was broken in the hole area. Open-hole GFRP‌ specimens were all broken in the hole area and simple specimens mainly in several regions in the gauge length range. Scanning Electron Microscopy (SEM) images recorded from the hole area of ​​GLARE‌ specimens clearly show that local debonding in the area around the hole caused the breakage of the specimen. In addition, the ratio of the ultimate stress of the simple GFRP‌ specimen to the open-hole specimen is 1.18 and the same ratio is 1.07 for GLARE‌ specimens. This indicates less hole effect on the ultimate stress in GLARE specimens than in GFRP. Furthermore, curved fibers around the hole can be used to reduce damage due to fracture and delay in its occurrence.

Theoretical models of void nucleation and growth for ductile metals under dynamic loading: A review

Void nucleation and growth under dynamic loading are essential for damage initiation and evolution in ductile metals. In the past few decades, the development of experimental techniques and simulation methods has helped to reveal a wealth of information about the nucleation and growth process from its microscopic aspects to macroscopic ones. Powerful and effective theoretical approaches have been developed based on this information and have helped in the analysis of the damage states of structures, thereby making an important contribution to the design of damage-resistant materials. This Review presents a brief overview of theoretical models related to the mechanisms of void nucleation and growth under dynamic loading. Classical work and recent research progress are summarized, together with discussion of some aspects deserving further study.

Combining nanosized elementary building blocks of soft and hard matter to create strong, damage resistant materials

Creating strong materials at 325 degrees Celsius using particles in the nanometer range that arrange perfectly in supercrystals via self-assembly

Radiation Effects in the Crystalline-Amorphous SiOC Polymer-Derived Ceramics: Insights from Experiments and Molecular Dynamics Simulation.

Radiation-tolerant materials are in great demand for safe operation and advancement of nuclear and aerospace systems. Nanostructuring is a key strategy to improve the radiation tolerance of materials. SiOC polymer-derived ceramics (PDCs) are unique synthetic nanocomposites consisting of β-SiC nanocrystals and turbostratic graphite distributed in amorphous SiOC matrix, which are "all-rounder" materials for many advanced structural and functional applications. Radiation effects in the crystalline-amorphous system have been investigated in detail by experiments and molecular dynamics (MD) simulations. The results indicate that the amorphous SiOC structure retains amorphous accompanied by redistribution of the Si-containing tetrahedra. The graphite is shown to amorphize more easily than β-SiC nanocrystals under the same irradiation condition. The sample richer in oxygen, namely, containing more amorphous SiOC, shows less disordering of graphite, resulting from greater mitigation of radiation damage by the amorphous phase as efficient sinks. This study provides details of the microstructure evolution of SiOC PDCs under ion irradiation, as well as insights for the design and development of advanced ion damage-resistant materials.

Microstructural design strategy to maintain the brittle fracture toughness of hard-soft dual phase steel after cyclic plastic strain

Superstructures are seriously damaged because of plastic deformation when natural disasters, such as large earthquakes or unexpectedly large waves, occur. Therefore, there is a need to develop materials that are resistant to damage and fracture while maintaining a certain level of strength. In this paper, the difference in material toughness changes when cyclic prestrain occurs among different ferrite/pearlite two-phase microstructures were investigated. Synthetic analysis using strain gradient plasticity (SGP) theory, one of the crystal plasticity theories, was carried out, and conventional macroscopic material damage consideration rules were employed. Then, it was suggested that the amount of material damage changes among the different microstructures. In addition, a parametric study using SGP theory is performed to suggest directions for the microstructural design of steel with a lower risk of brittle fracture due to plastic deformation. As a result, damage-resistant materials with sufficient strength can be proposed.

Interface failure in nacre-like alumina

Bioinspired ceramic-ceramic composites based on alumina platelets with a glassy interphase have recently emerged as a new class of strong and damage-resistant materials. Understanding the fracture properties of nacre-like alumina requires to know the properties of each of its components. However, only the platelets have been individually tested so far. Here we characterize at a micro scale the fracture properties of an aluminosilicate glass interphase. Micro-cantilevers prepared by FIB are tested to characterize the failure of interfaces with different angles, and thus undergoing different combined shear and tensile stress. The interface failure appears to be mainly driven by the opening stress that predominates over shear stress. It results in a local maximum opening stress of 0.72 ± 0.18 GPa, against 3 GPa for a pack of perpendicular and aligned platelets. These results should help understand the bulk properties of nacre-like alumina composites and enable a rational design of their components and microstructures.

Low velocity impact of Kevlar and ultra high molecular weight polyethylene (UHMWPE) reinforced epoxy composites

Low velocity impact of Kevlar and ultra high molecular weight polyethylene (UHMWPE) reinforced epoxy composites

Mechanical and Impact Properties of Packaging-Waste/E-Glass/Epoxy Sandwich Composites for Construction Applications

Using textile structural composites improves day by day in various industries due to their high specific strength and modulus, good fatigue and corrosion resistance. The most important reasons for the increased use of textile structural composites are the increased expectations for product performance and demand for lightweight materials in global markets. Rapid economic growth, urbanization, rising in population and welfare level lead to an increased amount of waste production. In Turkey, the annual average of solid waste is 25 million tons and 20% of this waste consists of packaging waste. In this study, a new sandwich material was developed for construction applications with low cost and high performance by using box wastes as core and E-Glass woven fabric as sheet materials. The mechanical properties were investigated by 3-point bending test and their impact behavior was compared after low-velocity impact tests in different energy levels. The core material had a negligible bending strength. The bending load of sandwich composites was dramatically higher than those of face material. Low-velocity impact results showed that absorbed energy and damaged area increased with increasing impact energy level. It could be concluded that the developed sandwich composites absorb more energy with small damaged areas and therefore can be considered as damage resistant materials for constructional applications as door and siding. The thermal insulation properties of these new sandwich composites will be also investigated in future researches.

Corrosion Analysis of Damage Resistant Materials used in Military Armoured Vehicles in Poisonous Gas Environment

With the improvement of China’s military strength, military armoured vehicles are very effective in dealing with various harsh environments. The poisonous gas environment is very serious against the body of the military armoured vehicle. For this reason, the damage-resistant material for the car needs to be developed, and the corrosion resistance of the material is analysed. Metal and polymer damage resistant materials are selected as research objects. In the three environments of alkaline poison gas, industrial poison gas and acid gas, the outdoor exposure test is carried out, and the indoor accelerated test under the combined environmental factors is implemented to obtain the mechanism of corrosion and aging behaviour of the typical material of the vehicle. Experiments show that the damage resistant material can effectively enhances the corrosion resistance of the car body in a poisonous gas environment.

Combining high hardness and crack resistance in mixed network glasses through high-temperature densification

Obtaining a combination of high toughness and strength is crucial for most structural materials, but unfortunately these tend to be mutually exclusive. The search for strong and tough damage-resistant materials has thus typically been based on achieving an acceptable compromise between hardness and crack resistance. Focusing here on brittle oxide glasses, we propose a new strategy for overcoming this conflict by identifying new structural motifs for designing hard and crack-resistant glasses. Specifically, we report that surprisingly there is no decrease in the densification contribution to deformation of a mixed network ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}\ensuremath{-}{\mathrm{B}}_{2}{\mathrm{O}}_{3}\ensuremath{-}{\mathrm{P}}_{2}{\mathrm{O}}_{5}\ensuremath{-}\mathrm{Si}{\mathrm{O}}_{2}$ bulk glass following predensification of the glass at elevated temperature. Hitherto unique to this glass composition, the treatment reduces the residual stress during subsequent sharp contact loading, which in turn leads to a simultaneous increase in hardness and crack resistance. Based on structural characterization, we show that the more densified medium-range order of the hot compressed glass results in formation of certain structural states (e.g., nonring trigonal boron), which could not be reached through any composition or thermal path. This work thus shows that accessing such ``forbidden'' structural states through the identified densification at elevated temperatures offers a way forward to overcome the conflict of strength versus toughness in structural materials.

Dealloying of Noble-Metal Alloy Nanoparticles

Dealloying is currently used to tailor the morphology and composition of nanoparticles and bulk solids for a variety of applications including catalysis, energy storage, sensing, actuation, supercapacitors, and radiation damage resistant materials. The known morphologies, which evolve on dealloying of nanoparticles, include core-shell, hollow core-shell, and porous nanoparticles. Here we present results examining the fixed voltage dealloying of AgAu alloy particles in the size range of 2-6 and 20-55 nm. High-angle annular dark-field scanning transmission electron microcopy, energy dispersive, and electron energy loss spectroscopy are used to characterize the size, morphology, and composition of the dealloyed nanoparticles. Our results demonstrate that above the potential corresponding to Ag(+)/Ag equilibrium only core-shell structures evolve in the 2-6 nm diameter particles. Dealloying of the 20-55 nm particles results and in the formation of porous structures analogous to the behavior observed for the corresponding bulk alloy. A statistical analysis that includes the composition and particle size distributions characterizing the larger particles demonstrates that the formation of porous nanoparticles occurs at a well-defined thermodynamic critical potential.

Use of Ga Doping to Suppress Optical Damage in Near-Stoichiometric LiNbO3 Crystals

We investigated the effect of Ga doping on optical damage (photorefractive damage) in near-stoichiometric LiNbO3 (SLN) crystals. SLN crystals doped with Ga (Ga:SLN) were grown from a Li-rich solution by a top-seeded solution growth method. The optical damage resistance of the crystals was investigated at 532 nm. Crystals with a Ga doping concentration of at least 0.49 mol % showed no optical damage. The Ga doping shifted the OH- absorption peak position from 2.88 to 2.85 µm for crystals with a 0.49 mol % concentration. This concentration is lower than the 1 mol % Mg doping concentration required to suppress optical damage in SLN crystals. This attractive optical damage resistance characteristic makes Ga:SLN crystals another candidate as an optical damage resistant material, in addition to Sc-doped SLN crystals, for applications such as electrooptic devices and quasi-phase-matched frequency converters.

Materials and design interface

The unprecedented demands faced by fusion structures primarily derive from severe time varying thermal-mechanical loading of complex, large scale, and highly interconnected heat transfer-energy conversion structures. This grand challenge is often much too narrowly couched in terms of the development of radiation damage resistant materials, while the enormously larger challenge is the creation of material systems and multifunctional structures. In addition, the fusion system designer is faced with the untenable situation that neither the fully functional materials, nor the requisite computational tools, nor experimental simulation facilities currently exist for reliable integrity and lifetime assessments of fusion reactor structures. Considering the absence of material information and design tools, neither the materials nor the fusion designer can follow standard design processes. The design process has to become actively materials-related while materials development must closely follow design process needs. This indispensible interaction between materials and design processes leads to a ‘concurrent materials-structure design’ path, which is necessary to meet the enormous materials-structural engineering challenges of fusion.

Conceptual design of the international fusion materials irradiation facility (IFMIF)

The International Fusion Materials Irradiation Facility (IFMIF) conceptual design is complete. The two-year effort was carried out as an activity of the IEA Executive Committee on Fusion Materials. Specialists from Europe, Japan, the United States and the Russian Federation came together in a series of meetings and workshops to define the concepts for the technical systems and the overall design and cost estimate. The goal of the IFMIF is to provide an irradiation facility for use by fusion material scientists in the search for low activation and damage resistant materials. An accelerator-based neutron source has been established through a number of international studies and workshops as an essential step for near-term materials development and testing. IFMIF would also provide calibration and validation of data from fission reactor and other accelerator-based irradiation testing. The design concept consists of a deuteron accelerator producing particle energies in the range of 30–40 MeV. The deuterons interact with a flowing liquid lithium target (D–Li) producing high energy neutrons with a peaked flux around 14 MeV. The resulting high energy neutrons will interact with a test assembly to irradiate test samples of candidate materials up to full lifetime of anticipated use in future fusion energy reactors.

Overview of the International Fusion Materials Irradiation Facility (IFMIF) Conceptual Design Activity

The goal of the International Fusion Materials Irradiation Facility (IFMIF) is to provide an irradiation facility for use by fusion material scientists in the search for low activation and damage resistant materials. An accelerator-based neutron source has been established through a number of international studies and workshops as an essential step for materials development and testing. IFMIF would also provide calibration and validation of data from fission reactor and other accelerator based simulation irradiations. It would generate material-specific activation and other radiological properties and analysis of data for safety, maintenance, recycling, decommissioning and waste disposal. 5 refs., 2 figs.

Neutron irradiation facilities for fission and fusion reactor materials studies

The successful development of energy-conversion machines based upon nuclear fission or fusion reactors is critically dependent upon the behavior of the engineering materials used to construct the fuel containment and primary heat extraction systems. The development of radiation damage-resistant materials requires irradiation testing facilities that reproduce, as closely as possible, the thermal and neutronic environment expected in a power-producing reactor. The Oak Ridge National Laboratory (ORNL) reference core design for the Center for Neutron Research (CNR) reactor provides for instrumented facilities in regions of both hard and mixed neutron spectra, with substantially higher fluxes than are currently available. The benefits of these new facilities to the development of radiation damage resistant materials are discussed in terms of the major US fission and fusion ractor programs.