Tensile Strength Σb Research Articles

Corrosion and mechanical properties of bioresorbable composite based on Fe-Cu-hydroxyapatite powders

In this work, bimetallic Fe-Cu nanopowders with the addition of hydroxyapatite (HAp) were used for the fabrication of composite biodegradable material suitable for extrusion additive manufacturing processes. Varying the metal and organic binder constituents in the feedstock has led to high performance composite material. Increasing the organic binder content in the initial feedstock from 50 to 60 wt% contributes to the reduction of porosity of the obtained composites from 20.6 % to 8.9 %. The 45Fe-Cu-HAp samples were characterized by the highest mechanical properties in the tensile test: yield strength σ0.2 being 110 MPa and tensile strength σB being 150 MPa. The Young's modulus of all composites is close to that of the cortical bone tissue modulus (≈ 15 GPa). The microhardness of the composite has been shown to exceed that of pure iron more than in 2 times. Corrosion tests have demonstrated that the composite material with minimal content of the organic binder (50Fe-Cu-HAp) showed the highest corrosion rate, which makes it more attractive for its application in the fabrication of a biodegradable implant. From the findings, the presented composite material showed significant antibacterial activity (more than 99 % reduction) against S. aureus. The composites showed excellent biocompatibility against sensitive fibroblast cell line 3T3. The more than 90 % cell viability was observed after 24 hours incubated with sample.

Effects of Ultra-Low Temperatures on the Mechanical Properties and Microstructure Evolution of a Ni-Co-Based Superalloy Thin Sheet during Micro-Tensile Deformation.

With the development of product miniaturization in aerospace, the nuclear industry, and other fields, Ni-Co-based superalloys with excellent overall properties have become key materials for micro components in these fields. In the microforming field, size effects significantly impact the mechanical properties and plastic deformation behavior of materials. In this paper, micro-tensile experiments at room temperature and an ultra-low temperature were carried out to study the effects of initial microstructure and deformation temperature on the deformation behavior of Ni-Co-based superalloy thin sheets. The results show that as the ratio of specimen thickness to grain size (t/d) decreased from 8.6 to 2.4, the tensile strength σb decreased from 1221 MPa to 1090 MPa, the yield strength σs decreased from 793 MPa to 622 MPa, and the elongation decreased from 0.26 to 0.21 at room temperature. When t/d decreased from 8.6 to 2.4, σb decreased from 1458 MPa to 1132 MPa, σs decreased from 917 MPa to 730 MPa, and the elongation decreased from 0.31 to 0.28 at ultra-low temperatures. When t/d decreased from 8.6 to 2.4, the surface roughness of the specimen increased from 0.769 to 0.890 at room temperature and increased from 0.648 to 0.809 at ultra-low temperatures. During the microplastic deformation process of Ni-Co-based superalloy thin sheets, the coupled effects of surface roughening caused by free surface grains and hindered dislocation movement induced by grain boundary resulted in strain localization, which caused fracture failure of Ni-Co-based superalloy thin sheets.

Production, Mechanical and Functional Properties of Long-Length TiNiHf Rods with High-Temperature Shape Memory Effect.

In the present work, the possibility of manufacturing long-length TiNiHf rods with a lowered Hf content and a high-temperature shape memory effect in the range of 120-160 °C was studied. Initial ingots with 1.5, 3.0 and 5.0 at.% Hf were obtained by electron beam melting in a copper water-cooled stream-type mold. The obtained ingots were rotary forged at the temperature of 950 °C, with the relative strain from 5 to 10% per one pass. The obtained results revealed that the ingots with 3.0 and 5.0 at.% Hf demonstrated insufficient technological plasticity, presumably because of the excess precipitation of (Ti,Hf)2Ni-type particles. The premature destruction of ingots during the deformation process does not allow obtaining high-quality long-length rods. A long-length rod with a diameter of 3.5 mm and a length of 870 mm was produced by rotary forging from the ingot with 1.5 at.% Hf. The obtained TiNiHf rod had relatively high values of mechanical properties (a dislocation yield stress σy of 800 MPa, ultimate tensile strength σB of 1000 MPa, and elongation to fracture δ of 24%), functional properties (a completely recoverable strain of 5%), and a required finishing temperature of shape recovery of 125 °C in the as-forged state and of 155 °C after post-deformation annealing at 550 °C for 2 h.

Mechanism of grain refinement and mechanical property enhancement of Ti-45Al-8Nb alloy by directed laser deposition

Directed laser deposition (DLD) as an important additive manufacturing process, has a good application prospect for the fabricating of complex high Nb-TiAl alloy parts in aerospace and energy industries. The mechanical properties of parts manufactured by DLD are affected by the interlamellar spacing of precipitated phases. In this paper, Ti-45Al-8Nb alloy specimens were manufactured by DLD, and the interactions between the semi-coherent interfaces, deformation twins, and dislocations were analyzed by transmission electron microscopy (TEM), it revealed the strengthening mechanism of interlamellar spacing on mechanical properties of Ti-45Al-8Nb alloy. The results indicate that the laser power is one of the important factors affecting the interlamellar spacing, and the microstructures of the specimens are composed of α2 phase, γ phase, and B2 phase. By the laser power adjusting, the interlamellar spacing λ decreases by 40.1%, the microhardness of the alloy was increased by 15.9%, and the tensile strength increased by 14.8%. Also, the relationship between the tensile strength σb and the interlamellar spacing λ satisfies the Hall-Petch relationship: σb=161.4+3204λ−1/2. The obstruction and absorption of dislocation motion by the lamellar interface and deformation twins are the main reasons for the improved mechanical properties of the alloy.

ИССЛЕДОВАНИЕ СТРУКТУРЫ И МЕХАНИЧЕСКИХ СВОЙСТВ ОБРАЗЦОВ, ПОЛУЧЕННЫХ МЕТОДОМ СЕЛЕКТИВНОГО ЛАЗЕРНОГО СПЛАВЛЕНИЯ ИЗ МЕТАЛЛИЧЕСКОГО ПОРОШКА ЖАРОПРОЧНОГО СПЛАВА ВЖ-159 (ХН58МБЮ)

This paper presents the results of determining the optimal parameters of selective laser melting (SLM) of the metal powder of the high-temperature alloy VZh-159 (KhN58MBYu). Empirically and using mathematical methods for planning and analyzing experiments to determine the effect of technological parameters of fusion on the tensile strength of the material, rational SLM modes have been established, namely, laser emission power, hatching, scanning speed. The laser power P (X1) and scanning speed v (X2) were chosen as the main variable parameters of the full-factor experimental design, and the tensile strength σB, MPa (Y), was presented as a dependent variable on the selected factors. The mechanical properties of the samples produced by the SLM were determined, which also depended on the volumetric energy density, which is equal to the ratio of the laser power to the product of the scanning speed, hatching, and layer thickness. During the experiment, it was possible to obtain an acceptable quality indicator - mechanical properties, for a certain range of technological parameters of SLM. A study of the microstructure of the material of produced samples of the VZh-159 (KhN58MBYu) heat-resistant alloy was carried out, and chemical and granulometric analysis of the initial powder was carried out.

Hardening the rolling surface of the wheels bandage after mechanical treatment

Article describes calculated argumentation of the striker sealing surface, in the form of the two cylinders with parallel axes model of loading, having an effect on the rim surface of the wheel pairs of rolling-stock. There has been presented a calculation variant of the depth of hard running surfacing of the rolling-stock wheel pairs. Installation of deep hardening of rolling surfaces of wheel sets allows the special striker to create certain forces on the rolling surface of the wheel rim, to deform the surface layer to a certain depth, thereby increasing the hardness of the deformed surface. The article presents the technology for hardening the wheel running surface by loading the surface of the wheel set bandage, by means of the deep hardening installation with the creation of strain stress in the surface layers for several combinations of tensile strength σB and velocity σT of various bandage materials.

A new β-Ti alloy with good tensile properties by the mixed microstructure characteristics of α phase

In this study, the mechanical properties, microstructural characteristics and deformation behavior of a novel high-strength metastable β alloy Ti-6.5Cr-4.5Sn-4.5Mo (wt %) were investigated. By obtaining α phase mixed microstructure with different size, morphology and orientation combinations in β matrix, a good combination of tensile strength σb~1305 MPa and total elongation ɛf~13.4 % was achieved. The microstructural characteristics of α phase consisting of discontinuous thin grain boundary α phase (αGB), lamellar α colonies and acicular αs precipitates were obtained by the solution treatment above β transus for a short time plus subsequent aging treatment after the heavy cold rolling. Detailed TEM analysis shows that it is difficult to deform for acicular αs precipitates due to their fine-scale, leading to a large number of α/β interfaces acting as dislocation barriers, which may ultimately result in an improvement on strength of the alloy. Compared with αs, the αGB and lamellar α colonies are soft, which could produce the large enough deformation and allow dislocations to generate and accumulate within them, so that it is beneficial to improve the mechanical properties of the alloy. Stress-relaxation experiments show that the sample with a uniform and finer distribution of α precipitate has a larger value of mobile dislocation ρm/ρm0 after relaxation, implying that most of the mobile dislocations remains in the sample, which results in the ultrahigh strength meanwhile accepted ductility in the specimen.

Effect of line energy density in repairing 34CrNiMo6 steel by electron beam remelting

The role of the line energy density of electron beam remelting in repairing damaged 34CrNiMo6 parts was investigated. Remelting technology can be used to rapidly repair defects with superior performance, but the value of the heat input during operation was difficult to control, which has a substantial impact on the microstructure and mechanical properties of the parts. The line energy density Q was introduced to calculate the experimental parameters. The microstructure was observed at different regions of the sample, and its mechanical properties were analyzed. From the results, the following conclusion was drawn. An appropriate increase of line energy density could increase the depth and width of remelting to improve the remelting efficiency. Under a low line energy density (Q1), the mainly thermal cycle on 34CrNiMo6 steel was tempering rather than the preheating. With the increase of energy density, the preheating effect of ex-remelting came into sight, and the martensite of repaired zone with energy density Q2 and Q3 became coarse. As to the enhanced diffusion of carbon, the amount and size of carbides precipitated from ferrite increased. The microhardness decreased with the increase of energy density, the max value was about 660 HV (Q1) and the min was 330 HV (Q3). Tensile properties in different Q were similar, the max tensile strength σb was 845 MPa by remelting. The samples after quenching and tempering (QT) exceeded the forging standard even for the lowest strength value (1013 MPa). The fracture mode of remelted samples was brittle fracture in low energy density (Q1), and changed to quasi-cleavage fracture at energy density Q2 and Q3. All the modes of the QT samples were ductile fractures.

EVALUATION OF MATERIAL QUALITY BY NON-DESTRUCTIVE METHOD

Introduction. Different approaches are used to assess the quality of metal by non-destructive methods. These include ultrasound, X-ray, optical and electron microscopy, and mathematical prediction. The latter differ in the ability to improve the obtained models by adjusting the arguments (in this case, the studied parameters of technology). This problem is especially acute when assessing the quality criteria for solid metal castings, which include cast iron rolls. Materials and methods. As a material for the study, high-grade rolled cast iron of СПХН was selected to study the effect of its chemical composition on mechanical properties (HB hardness; tensile strength σB; flexural strength σзгин). The structure of the working layer of cast iron barrels (up to 50 mm from the surface) consisted of a pearlite matrix (70… 85 %), ledeburite eutectic cementite (13… 28 %) and plate-shaped graphite (up to 2,5 %). The results of the experiment. Using the matrix of experimental planning, mathematical models of forecasting the selected quality criteria of cast iron depending on the influence of elements of chemical composition on them are obtained. In order to increase the results of the forecast of mechanical properties, a symbiosis of expert and experimental evaluations was used in the work. The application of this approach has made it possible to reduce the cost of conducting mechanical examinations, which is relevant for the considered periodic technology. The values of the rows of the planning matrix, where there were not enough experimental estimates of mechanical properties, were replaced by expert estimates. Rows 6 and 13−16 of the matrix provide expert assessments. The pairwise correlation coefficients of the obtained regression equations vary in the range of 0,71…0,83, which allows them to be used for practical purposes to predict and adjust the mechanical characteristics in the process of manufacturing cast iron rolls. Conclusions. The influence of elements of chemical composition (carbon, silicon, manganese, phosphorus, sulfur, chromium and nickel) of rolled cast iron of SPHN performance on its mechanical properties: σB, σзгин and HB is investigated. It is recommended to apply the obtained equations of estimation of mechanical properties at the enterprise ДЗПВ of Dnipro for their operative forecast.

A Study on the smelting process of low carbon steel scrap and sponge iron in medium frequency induction furnace for production of front bumper beams

MS1200 steel grade is now widely utilized in the automotive sector because it is a good solution for the current trend of vehicle chassis frame construction. This research presents a technology procedure for producing MS1200 steel grade from low carbon steel scrap and sponge iron – a product of MIREX Vietnam. The smelting using up to 30 % sponge iron briquettes combined with low carbon scrap, FeSi, FeMn, FeCr, FeTi,… was realized in a medium frequency induction furnace. The heat treatment for forged steel was performed to obtain required properties. The steel product has the following properties: tensile strength σb = 1280 MPa, yield strength σ0.2 = 990 MPa and impact toughness ak = 769 J/mm2, that meets the need of industrial use.

Xylose-Based Polyethers and Polyesters Via ADMET Polymerization toward Polyethylene-Like Materials

One of the challenges of developing bioderived polymers is to obtain materials with competitive properties. This study investigates the structure-properties relationships of polyesters and polyethers that can be derived from d-xylose through metathesis polymerization, in order to produce bioderived plastic materials that are sourced from sustainable feedstocks and whose properties can compete with those of polyolefins such as polyethylene. Bicyclic diol 1,2-O-isopropylidene-α-d-xylofuranose was coupled with ω-unsaturated fatty acids and alcohols of different chain lengths (C11, C5, C3), and the resulting α,ω-unsaturated esters and ethers polymerized via an acyclic diene metathesis (ADMET) polymerization using a commercial Grubbs second-generation catalyst, obtaining polymers with Mn up to 63.0 kg mol–1. Glass transition temperatures (Tg) decreased linearly with increasing chain length and were lower for polyethers (−32 to 14 °C) compared to polyesters (−14 to 45 °C). ADMET polymers could be modified postpolymerization by reacting their internal carbon–carbon double bonds. Thiol–ene reaction with methyl thioglycolate lowered the Tg while allowing insertion of additional functional groups. Alkene hydrogenation turned the polyester and polyether with C20 hydrocarbon linkers into semicrystalline polymers with Tm ≈ 50 °C. The latter, when cast into films, displayed remarkable polyethylene-like properties. Hot-pressed films proved ductile materials (Young modulus Ey 60–110 MPa, elongation at break εb 670–1000%, ultimate tensile strength σb 8–10 MPa), while uniaxially oriented films proved very strong yet flexible materials (Ey 190–200 MPa, εb 160–350%, σb 43–66 MPa). Gas barrier properties were comparable to those of commercial polyolefins. Polyethers were resistant to hydrolysis, while polyesters depolymerized under alkaline conditions.

Correlation between microstructure and mechanical properties of columnar crystals in the directionally solidified Mg-Gd-Y-Er alloy

The Mg-4.58Gd-0.45Y-0.01Er alloys with different volume fractions of columnar crystals in hard orientation (orientation factor of <a> basal plane slip system is less than 0.2) were prepared by changing the pulling rate to regulate the crystal growth orientation. Tensile tests were performed on the Mg-4.58Gd-0.45Y-0.01Er alloy at room temperature, and the structure after deformation was investigated by electron backscatter diffraction (EBSD). Subsequently, the strengthening mechanism of columnar crystals in hard orientation was explored. The results show if orientation factors of <a> basal plane slip system of columnar crystals are all greater than 0.4 (soft orientation), the alloy has low yield strength σs (64 MPa), but great work hardening ability, and ultimate tensile strength σb and elongation δ are 114 MPa and 37.3%, respectively. If orientation factors of <a> basal plane slip system of columnar crystals are all less than 0.2 (hard orientation), the alloy has high strength (σs, 125 MPa), but poor plasticity (δ, 6.32%). If the “hard orientation” and the “soft orientation” columnar crystals are arranged alternately along the direction perpendicular to the crystal growth, the alloy has both superior strength (σs, 102 MPa) and excellent plasticity (δ, 22.5%) at room temperature. The improved comprehensive mechanical property can be attributed to two factors. On the one hand, the “hard orientation” columnar crystals can prevent the “soft orientation” crystals deforming, so the strength is improved. On the other hand, the “hard orientation” columnar crystals themselves can withstand a certain amount of deformation to retain appropriate plasticity.

Direct Evidence of Symmetry between Bilateral Human Corneas in Biomechanical Properties: A Comparison Study with Fresh Corneal Tissue

Purpose. To investigate the difference between the eyes from the same human with respect to the biomechanical properties of fresh corneal tissues and investigate the assumption of similarity of the corneal biomechanical properties between the eyes. Methods. Strip specimens extracted through a small incision lenticule extraction (SMILE) surgery were tested using a uniaxial tensile test. The specimens were extracted vertically. Low-strain tangent modulus (LSTM), high-strain tangent modulus (HSTM), and tensile strength (σb) were the biomechanical parameters used in the comparison of the eyes from the same human. Results. Ninety corneal specimens from 45 persons were included in this study. The LSTM of the left and right eyes were 1.34 ± 0.52 and 1.37 ± 0.46 MPa, while the HSTM were 50.53 ± 7.51 and 49.41 ± 7.01 MPa, respectively. There was no significant difference between the eyes in terms of LSTM, HSTM, andσbP=0.813, 0.335, and 0.605, resp.. The LSTM and HSTM were significantly correlated with the spherical equivalent (SE) (P≤0.01, P=0.001, resp.). Conclusions. The assumption that the corneal biomechanical properties of the eyes from the same human are similar has been confirmed for the first time using fresh human corneal tissue. This finding may be useful in further biomechanical studies.

A practical model for efficient anti-fatigue design and selection of metallic materials: II. Parameter analysis and fatigue strength improvement

In the first paper, a Y-T-F model was proposed based on the restrictions of both strength and plasticity; the corresponding applications on the fatigue strength prediction have also been discussed. In this second paper, the emphasis will be put on the issues of fatigue strength improvement. Based on the primary form of the Y-T-F model, the parameters are further analyzed and quantified, to clarify the influences of various factors on fatigue strength. Firstly, the damage capacity C is proved to be sensitive to the elastic modulus E, which could change with the alloying components and nano-scaled grain boundaries; the increase of E would lead to the increasing C, thus increase the fatigue strength. Secondly, the microstructure characteristic coefficient a, as well as the yield strength σy and tensile strength σb in the crack initiation region could be influenced by the processing mode, grain size and microstructure uniformity of materials; the change of microstructure characteristics would affect the changing tendency of tensile strength--fatigue strength relation via varying the values of a, σy and σb. Thirdly, the damage weight coefficient ω is found to be a reflection of the fatigue strength declination induced by defects; the defect dimension D, the defect shape correlated stress concentration coefficient Kt, as well as the strengthening level of matrix materials σb are all corresponding factors. Quantified correlations between the above parameters and corresponding factors are comprehensively built up, hence obtaining the influences of either a single factor or multiple factors on fatigue strength. This further developed Y-T-F model would be helpful to clarify the direction of fatigue strength improvement, and contribute to the anti-fatigue design optimization of metallic materials.

Corrosion state of oil cracking reactors as the main factor of fire and explosion safety during their operation

The corrosion and mechanical properties of the oil catalytic cracking reactor vessel made of stainless steel Y1-T (1X18N9T) after its operation for more than 60 years have been determined. The chemical composition of the reactor metal meets the requirements of GOST and involves the isolation of non-metallic inclusions of manganese sulfide in its structure, which cause the development of pitting, and chromium carbides, which are responsible for the propensity to intergranular corrosion. After long-term operation, the mechanical characteristics of the metal (tensile strength σb, yield strength σt, elongation δ, relative contraction Ψ), determined using cylindrical samples at a temperature of 20 °C (GOST 1497-84) and at an operating temperature of 465 °C (GOST 9651), on the breaking machine TC 110M-50, correspond to the standard values. Metallographic studies carried out using an optical microscope “Axio Observer Z1m « at magnifications of X25, X75, x125, X200, X250, X400, X500, x1000, X2000 showed that long – term operation of the metal at a temperature of 375…425 °C with periodic overheating up to 550…650 °C leads to the release of excess phases, namely, chromium carbides and titanium carbonitrides. The metal grain boundaries are enriched with Cr23C6 carbides, which cause a loss of resistance against intergranular corrosion. Corrosion pitting and weakened metal grain boundaries are promoters of the occurrence of corrosion cracks. The most dangerous areas of large-size equipment are welded joints and zones of thermal influence. A mandatory condition for fire and explosionproof operation of the refinery is periodic diagnostics of the corrosion state of the equipment in order to identify and timely eliminate potentially dangerous areas, the probability of which breaching with subsequent spillage and fire of oil and petroleum products is the highest.

Second phase particles and mechanical properties of 2219 aluminum alloys processed by an improved ring manufacturing process

2219 Al alloy has been used to manufacture the launch vehicle storage tank transition ring, but the large ring obtained in conventional manufacturing processes still suffers from severely agglomerated coarse second phase particles and poor mechanical properties. An improved process (forging at 510 °C with 20% deformation and at 240 °C with 50% deformation, then rolling at 240 °C with 30% deformation, followed by solid solution at 538 °C for 4 h and T8 treatment) for 2219 Al alloy large ring manufacturing was proposed, and the corresponding simulation tests were carried out. The evolution of Al2Cu second phase particles and the mechanical properties of the produced workpieces were investigated. The results showed that the degree of crushing, dissolution, and precipitation of Al2Cu particles were significantly improved in the improved process, and the area fractions of Al2Cu coarse second phase particles after saddle forging and rolling were significantly reduced, leading to 2.4 times increase in area fraction of the θ′ phase after T8 treatment. More homogeneous slip occurred during the tensile testing process and intergranular fracture was the main fracture mechanism. The tensile strength σb, yield strength σs, and elongation δ in the radial direction of the 2219 workpieces were increased to 491 MPa, 388 MPa, and 13.1%, where were increases of 11%, 14%, and 68%, respectively. The uniformity in σb, σs, and δ of the 2219 workpieces increased by 57%, 38%, and 64%, respectively.

A high-strength Co–Fe–Ta–B metallic-glass phase enabled tensile plasticity in Co–Fe–Ta–B–O oxide glass matrix nanocomposites

Oxide glasses are intrinsically brittle at room temperature when loaded under tension. In this study, a high-strength CoFe-based metallic glass was used as a strengthening phase to make a Co–Fe–Ta–B–O oxide glass become stronger and ductile in tension. The developed metallic-glass-reinforced oxide glass matrix nanocomposite possessed a supra-nanometer-sized dual-phase structure. Owing to the dispersion strengthening effects, the nanocomposite showed a tensile strength σb of ∼2.7 GPa, about 29% higher than that of the single-phase oxide glass. Meanwhile, its tensile plasticity εp was enhanced from zero to ∼2.7%. The continuous glass/glass interfaces of the dual-phase mixture are thought to enable the tensile plasticity in the nanocomposite. Our results provide an approach to effectively enhance both the strength and tensile ductility of intrinsically brittle oxide glasses.

Особенности разрушения металлов при импульсном лазерном и пучково-плазменном воздействии

The features of the destructive effect of high-pressure generated under comparable conditions, namely, upon irradiation of target samples with pulsed laser radiation and beam-plasma flows created in Plasma Focus (PF) devices, on metal materials were studied. In both cases, close parameters of radiation-heat treatment were provided: power density q ~ 1010–1011 W/cm2 and pulse duration τ ~ 10 –100 ns. It have been shown that the double exposure of laser radiation to thin samples of vanadium and molybdenum with a thickness of 0.3 mm and 0.1 mm, respectively, leads to the formation of molten zones in the materials, inside which there were deep craters. The craters extended over the entire thickness of the samples, on the reverse side of which the recesses end with holes of ~ 0.1 mm for V and 0.2 mm for Mo. In a tungsten sample 0.2 mm thick, the depth of the craters in the molten zone was less than its thickness and there were microcracks on the back of the sample. Based on numerical estimates of the process under study, it was suggested that the observed effects are associated with the creation of high pressure zones of ~ 1 – 10 GPa in the irradiated targets, localized in microregions of radius r ~ 0.1 mm. In these zones, the behavior of the solid phase of the target materials, for which the tensile strength σB ≤ 1 GPa (V, Mo, W), under high pressure became close to the behavior of the liquid. The pseudo-liquid phase of the material was displaced from the center of the crater, where the pressure was maximum, to its periphery to the region of low pressure with the subsequent release of matter from the target through the irradiated surface at a speed of ~ 103 m/s. In experiments using the PF, the mechanism responsible for the formation of craters when a powerful pulsed laser radiation is applied to the target is not realized due to the different nature of the distribution of the absorbed energy density in the surface layer of the irradiated sample. The region in which the energy absorbed during the of particles implantation into the material was determined mainly by the average energy and the diameter of the ion beam (Еi ≈ 100 keV, d ~ 2 – 10 mm) and exceeds by one or two orders of magnitude the corresponding volume under laser irradiation.

Structural features and mechanical properties of Grade 4 titanium from VSMPO-AVISMA (Russia) and Grade 4 titanium from Carpenter Technology Corporation (USA), subjected to ECAP-Conform

In this paper, we analyze the microstructural features and mechanical properties of the Grade 4 titanium produced in Russia (VSMPO-AVISMA) and Grade 4 titanium from Carpenter Technology Corporation (USA). It is shown that during the ECAP-Conform processing and subsequent drawing, a homogeneous UFG structure is formed in both Ti materials, providing an enhanced level of mechanical properties with an ultimate tensile strength σB > 1200 MPa and an elongation to failure δ ~ 12%.

Fracture Toughness of CF-Plug Joints of Ti and Epoxy Matrix CFRP

A new method of linear connected joints (Ti/CF-plug/Epoxy) of Ti (Titanium) to Epoxy connected by CF-plug was innovated and developed, since fine carbon fibers (CFs) generate the extremely large friction force by their broad interface between metals and Epoxy polymer (M/Epoxy). Compared with glue and spontaneous adhesions of M/Glue/Epoxy and M/Epoxy, the new method remarkably improved the fracture toughness with maintaining light weight. To maintain the high joint strength of the Ti/CFW-CFJ/Epoxy, the Ni coating film on CF should control to bite the CF by molten Ti. The tensile strength (σb) and its strain (εb) of Ti/NiCFW-CFJ/Epoxy were higher than those of Ti/CFW-CFJ/Epoxy. In addition, increasing the CF-volume increases the σb. The CF-plug joint between Ti and Epoxy matrix CFRP apparently probably enhances the fuel efficiency, as well as safety level of airplane.