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Unlike metals for which the fracture characterization methods have been standardized in the context of linear elastic and elastic plastic fracture mechanics theories, for polymeric materials the linear and especially nonlinear theories of viscoelastic fracture mechanics have not been completely developed due to complexities regarding the viscoelastic nature of these materials. For rubbers, even the rate independent theories based on nonlinear finite elasticity have not been widely used. In practice, most researchers make use of the same methods as applied for metals to rubbers. In this paper, the common methods of fracture characterization of rubbers based on J integral and the different challenges regarding them are reviewed. Specificly, the energy dissipation effects in regions far from the crack tip and the correction methods proposed to compensate for these effects are discussed. Performing fracture toughness tests on SENT specimens of a rubbery material based on polybutadiene, it is shown that the well-known multiple specimen method for determination of Jc has a strong sensitivity to experimental errors that presents itself as initial crack length dependence of Jc values and is just useful when testing numerous specimens and removing the experimental errors. On the other hand, the locus method of dissipation correction gives a single reliable Jc value using a fewer number of specimens and with a considerably lower sensitivity to the experimental errors. Also, using this method the specimen length dependence of Jc values reported in the literature is removed, and hence, it is possible to obtain a dimension independent Jc value. [ABSTRACT FROM AUTHOR]

Financial regulators are challenged with finding the most efficient and effective ways to monitor banks given an expanding and complex international financial system. Market discipline has grown in importance as a way to discourage banks from taking on unnecessary risk. One of the main drivers of market discipline is information disclosure. While the literature on market discipline is expansive, there are no known studies on the impact of individual information disclosure requirements on market discipline. Our study investigates which specific disclosure requirements influence financial investors to discipline banks and which do not. We find that information disclosure requirements primarily reduce or have no impact on market discipline practices. [ABSTRACT FROM PUBLISHER]

Rural breast cancer survivors (RBCS) are at greater risk for poorer health outcomes and face greater treatment barriers compared to their urban counterparts, necessitating behavioral interventions tailored for the unique needs of RBCS. A systematic review of studies examining behavioral interventions delivered to RBCS living in the United States from 2000 to 2020 was conducted following PRIMSA guidelines. Nineteen unique studies were included: eight randomized controlled trials, two matched-control studies, six pre-post intervention feasibility studies, and three post-intervention satisfaction studies. Thirteen interventions aimed to improve psychosocial support, three to improve weight management, and three to improve education. Results indicate interventions' feasibility and acceptability. Six out of eight intervention conditions reported favorable outcomes compared to control conditions, suggesting promise for efficacy. However, variability in intervention objective, duration, delivery, and follow-up timing, and small sample sizes prevent overarching conclusions. Research involving larger sample sizes, higher quality control groups, and longer follow-up data is needed., (© 2020. Springer Science+Business Media, LLC, part of Springer Nature.)

This work demonstrated a simple, effective and economic method to fabricate robust superamphiphobic aluminum surfaces that showed super-repellency even towards very low-surface-tension liquids, including octane with a surface tension of 21.7 mN m−1. The dual microstep/nanopore structures were firstly constructed through combining chemical etching, anodization, and a subsequent pore-widening treatment. The pore-widening time that controlled the pore size and porosity determined the surface oil-repellent ability. With an appropriate pore-widening time, these nanopores broke down and were over-etched, and ultimately turned into large-area nanowire arrays. The hierarchical microstep/nanowire array architecture, when modified with fluorosilane, finally made the surface realize superamphiphobicity towards octane. The surface wettabilities of the hierarchical-nanopore structure and hierarchical-nanowire array structure towards various oils were investigated and compared in detail. More importantly, the final superamphiphobic surfaces simultaneously presented robust stabilities and high resistances to severe chemical and physical damage. The hierarchical-nanowire surfaces were able to repel strong HCl/NaOH solutions (25 °C), hot solutions (water, HCl/NaOH solutions, 30–100 °C), and even 98% concentrated H2SO4. Furthermore, when the surfaces were submerged in NaCl solution for 48 h, exposed in a thermal atmosphere (280 °C for 4 h), immersed in solvent, and stored under air conditions for 8 months, the super-liquid-repellency of the surfaces remained unchanged. They impressively sustained their superamphiphobicity after intensive scratching with an incisive blade, contaminated finger-contact, multiple bending to 180°, repeated peeling tests by adhesive tape, and reciprocating abrasion treatment under 500 g of force. The superior stability of the superamphiphobic surfaces is attributed to their stable surface structure and composition, and is believed to broaden their outdoor applications. [ABSTRACT FROM AUTHOR]

Nowadays, great interests are rising on aluminum alloys for the applications at elevated temperature, driven by the automotive and aerospace industries requiring high strength, light weight, and low-cost engineering materials. As one of the most promising candidates, Al-Mn-Mg 3004 alloys have been found to possess considerably high mechanical properties and creep resistance at elevated temperature resulted from the precipitation of a large number of thermally stable dispersoids during heat treatment. In present work, the effect of Fe contents on the evolution of microstructure as well as high-temperature properties of 3004 alloys has been investigated. Results show that the dominant intermetallic changes from α-Al(MnFe)Si at 0.1 wt pct Fe to Al(MnFe) at both 0.3 and 0.6 wt pct Fe. In the Fe range of 0.1-0.6 wt pct studied, a significant improvement on mechanical properties at elevated temperature has been observed due to the precipitation of dispersoids, and the best combination of yield strength and creep resistance at 573 K (300 °C) is obtained in the 0.3 wt pct Fe alloy with the finest size and highest volume fraction of dispersoids. The superior properties obtained at 573 K (300 °C) make 3004 alloys more promising for high-temperature applications. The relationship between the Fe content and the dispersoid precipitation as well as the materials properties has been discussed. [ABSTRACT FROM AUTHOR]

The mechanical properties and microstructure of sheets of an Al-4.7Mg-0.32Mn-0.21Sc-0.09Zr alloy deformed and annealed after rolling have been investigated. The total accumulated true strain was ε = 3.33-5.63, and the true strain at room temperature and at 200 °C was ε = 0.25-2.3. The strength properties of the sheets (yield stress σ = 495 MPa and ultimate tensile strength σ = 525 MPa) in the deformed state were greater than those after equal-channel angular pressing (ECAP) deformation. The mechanical properties of the deformed sheets after annealing depended on the size of subgrains inside the deformed grains bands with high-angle grain boundaries (HABs). With the increase in the annealing temperature from 150 to 300°С, the subgrain size increased from 80 to 300 nm. The relative elongation δ in the as-cast state and after annealing at 200-250°C (δ = 40-50%) was higher than that after annealing at 300-370°C (δ = 24-29%). [ABSTRACT FROM AUTHOR]

Ultra-long Boron Nitride Nanotubes (100-200 µm) based layered Al-BNNT-Al composites are fabricated by spark plasma sintering, followed by cold rolling. The BNNT mat is sputter coated with Al to engineer strong metal-nanotube interface. The BNNTs exhibit perfect alignment along the cold rolling direction. The tensile strength of the composite is found to be 200 MPa, which is 400% greater than the strength of pure Al (≈40 MPa). Young's modulus of this sandwich composite (≈134 GPa) is found to be double the modulus of pure Al (≈70 GPa) (with standard deviations less than 10%). Strengthening is explained by three major mechanisms: superior load transfer for long BNNT reinforcement, improvement in matrix-nanotube bonding due to trace amount of interfacial product formation, and crack bridging by directionally aligned long nanotubes. [ABSTRACT FROM AUTHOR]

Aluminium die-castings whose performance needed to be evaluated against the baseline were subjected to fatigue testing. The results showed lower than expected fatigue life and incorrect Weibull distribution of the data, as well changes in the failure location and fracture morphology. This was a clear indication that the casting parameters were inadequate. In addition, the microstructure analysis revealed the presence of flow-induced segregation patterns, entrapped oxide films, gas porosity, microshrinkage and dross. Die-cast parts typically exhibit some of these microstructural inconsistencies; however, in this case, the presence of atypical casting defects such as the numerous internal cold drops and cold shuts in the fracture surface pointed towards incorrect casting parameters and design as root cause. Further investigation determined that a different gating system, more prone to cold shut development – all other parameters being equal, was used to produce these parts. After improvements were made to the gating system, the evaluated castings achieved the desired quality of the baseline parts. [ABSTRACT FROM PUBLISHER]

The investigations presented in this paper describe surface treatment performed on samples of heat-treated cast magnesium and aluminium alloy. The structure and chemical composition as well as the functional and mechanical properties of the obtained gradient/monolithic films were analysed by high resolution transmission electron microscopy and scanning electron microscopy, Raman spectroscopy, the ball-on-disk tribotester and scratch testing. Moreover, investigation of the electrochemical corrosion behaviour of the samples was carried out by means of potentiodynamic polarisation curves in 1-M NaCl solution. The coatings produced by chemical vapour deposition did not reveal any delamination or defects and they adhere closely to the substrate. The coating thickness was in a range of up to 2.5 microns. Investigations using Raman spectra of the DLC films confirmed a multiphase character of the diamond-like carbon layer, revealing the sp² and sp³ electron hybridisation responsible for both the hardness and the friction coefficient. The best wear resistance test results were obtained for the magnesium alloy substrate - AZ 61, for which the measured value of the friction path length wa s equal to 630 m. [ABSTRACT FROM AUTHOR]

The interfacial reaction products and stress distribution in a selective laser melted Al12Si/SiC composite are studied using confocal Raman microscopy. Results reveal that needle-like Al4C3 and equiaxed Si are located at the interface between the Al matrix and SiC particles. This reaction is triggered by the high temperature within the SiC due to its high laser absorptivity. Raman frequency shifts to lower wavenumber are observed in both the SiC and Si, suggesting the existence of tensile stress within the interface. The tensile stress in SiC is higher in the build direction than in the direction perpendicular to the build direction. No such difference is observed in the Si. The reason is ascribed to the Gaussian distribution of the laser energy density and stress relief through the interfacial reaction. [ABSTRACT FROM AUTHOR]

Bulk metallic glasses (BMGs) can exhibit excellent combinations of strength and fracture toughness that cannot be achieved by traditional metals, making them attractive for load bearing, mechanical engineering applications. Furthermore, recent research on BMGs has shown that many early perceived shortcomings, such as apparent brittleness or poor fatigue resistance, are not as big of a problem as once thought. The purpose of this paper is to review some of the unique mechanical characteristics of BMGs along with some of the strategies that may be used to improve or exploit their characteristics so that BMGs may be used as structural materials in engineering applications. [ABSTRACT FROM AUTHOR]

Load carriage (LC) exercise in physically demanding occupations is typically characterised by periods of low-intensity steadystate exercise and short duration, high-intensity exercise while carrying an external mass in a backpack; this form of exercise is also known as LC exercise. This induces inspiratory muscle fatigue and reduces whole-body performance. Accordingly we investigated the effect of inspiratory muscle training (IMT, 50% maximal inspiratory muscle pressure (PImax) twice daily for six week) upon running time-trial performance with thoracic LC. Nineteen healthy males formed a pressure threshold IMT (n = 10) or placebo control group (PLA; n = 9) and performed 60 min LC exercise (6.5 km h-1) followed by a 2.4 km running time trial (LCTT) either side of a double-blind six week intervention. Prior to the intervention, PImax was reduced relative to baseline, post-LC and post-LCTT in both groups (pooled data: 13 ± 7% and 16 ± 8%, respectively, p < .05) and similar changes were observed post-PLA. Post-IMT only, resting PImax increased +31% (p < .05) and relative to pre-IMT was greater post-LC (+19%) and post-LCTT (+18%, p < .05), however, the relative reduction in PImax at each time point was unchanged (13 ± 11% and 17 ± 9%, respectively, p > .05). In IMT only, heart rate and perceptual responses were reduced post-LC (p < .05). Time-trial performance was unchanged post-PLA and improved 8 ± 4% after IMT (p < .05). In summary, when wearing a 25 kg backpack, IMT attenuated the cardiovascular and perceptual responses to steady-state exercise and improved high-intensity time-trial performance which we attribute in part to reduced relative work intensity of the inspiratory muscles due to improved inspiratory muscle strength. These findings have real-world implications for occupational contexts. [ABSTRACT FROM AUTHOR]

The high cost and time typically expended in the successful deployment of new materials into high-performance commercial products is attributable to multiple factors. The most significant of these include the heavy reliance on experiments, the persisting disconnect between multiscale experiments and multiscale models, the lack of a broadly accessible data and knowledge infrastructure that can support the implementation of a holistic systems approach, and the lack of a suitable framework for facilitating and enhancing the critically needed cross-disciplinary collaborations. The emerging discipline of materials data science and informatics (MDSI) promises to address these key technology gaps. The potential benefits to the materials innovation enterprise that could accrue from an aggressive adoption of the novel concepts and toolsets offered by MDSI are examined. A specific vision is expounded for the role of MDSI in bridging the large gap that exists between the multiscale materials experiments and the multiscale materials models. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the effect of Si-content and microstructure on mechanical properties of Al-Si-Mg alloys with the purpose of to develop high-strength cast aluminum alloys that are anodizable. The Si-content was 2.5, 3.5 and 5.5wt% Si, and both Sr-modified and unmodified conditions were used. The samples were produced using the gradient solidification furnace to generate awell-controlled microstructure. The resulting secondary dendrite armspacingwas 10 and 20μm. Themicrostructural features were evaluated by employing SEM/EDS and optical microscopy. Furthermore, computed tomography (CT) scan technology was used to provide a 3D view of high-density phases in the microstructure. The mechanical properties of these alloys were studied by means of tensile and hardness testing where the latter was performed on the macrolevel and microlevel. The results demonstrate clearly how the Si growth in the microstructure is restricted by increased cooling rate and modification and its role in strength development in Al-Si alloys. Additionally, the CT scan visualized the morphology of intermetallics and supported in identifying the oxide layer growth as a result of the anodizing process. [ABSTRACT FROM AUTHOR]

The Al-5% Cu alloy-based metal-matrix composite materials reinforced with 5-μm BC particles have been produced using mechanical mixing-in method. A process of addition of the BC particles into the melt has been developed. A homogeneous distribution of the BC reinforcing particles in the metal-matrix composite matrix was obtained. Using X-ray diffraction analysis, the formation of AlBC and AlB phases has been revealed at the interphase matrix/particle boundary, which indicates a good interaction in the phases. With increasing BC content in the matrix alloy, an insignificant increase in the porosity (from 1 to 3.1%) occurs. The average linear thermal-expansion coefficient is reduced from 24.5 to 22.6 × 10 K in the temperature range of 20-100°C. [ABSTRACT FROM AUTHOR]

Thermal conductivity of a rheocast component made from Stenal Rheo1 (Al-6Si-2Cu-Zn) alloy was investigated in as-cast, T5 and T6 conditions. The thermal conductivity measurement in different locations showed variation of this property throughout the rheocast component. The results of microstructural investigation revealed that the ratio of solute-lean α1-Al particles formed during slurry preparation to fine solute-rich α2-Al particles formed during secondary solidification had significant influence on thermal conductivity. The reduced amount of solutes in the α1-Al particles was determined as the root cause of higher thermal conductivity. A linear relation between the fraction of precipitates and the increase in thermal conductivity was obtained and silicon in solid solution is shown to have a dominant influence. As silicon was precipitated during the heat treatment, thermal conductivity increased. For an optimal combination of thermal and mechanical properties, it is therefore important to use an ageing temperature above the temperature of Si precipitation. [ABSTRACT FROM PUBLISHER]

The goal of the Materials Genome Initiative is to substantially reduce the time and cost of materials design and deployment. Achieving this goal requires taking advantage of the recent advances in data and information sciences. This critical need has impelled the emergence of a new discipline, called materials data science and informatics. This emerging new discipline not only has to address the core scientific/technological challenges related to datafication of materials science and engineering, but also, a number of equally important challenges around data-driven transformation of the current culture, practices, and workflows employed for materials innovation. A comprehensive effort that addresses both of these aspects in a synergistic manner is likely to succeed in realizing the vision of scaled-up materials innovation. Key toolsets needed for the successful adoption of materials data science and informatics in materials innovation are identified and discussed in this article. Prototypical examples of emerging novel toolsets and their functionality are described along with select case studies. [ABSTRACT FROM PUBLISHER]

This article examines the relationship between the amount of information disclosed by bank holding companies (BHCs) and the BHCs' subsequent risk-adjusted performance. Using data from the annual reports of BHCs with large trading operations, the author constructs an index that quantifies the BHCs' public disclosure of forward-looking estimates of market risk exposure in their trading and market-making activities. She then examines the relationship between this index and subsequent risk-adjusted returns in the BHCs' trading activities and for the firm overall. The key finding is that more disclosure is associated with higher risk-adjusted returns. This result is strongest for BHCs whose trading represents a large share of overall firm activity. More disclosure does not appear to be associated with higher risk-adjusted performance during the financial crisis, however, implying that the findings are a "business as usual" phenomenon. These findings suggest that greater disclosure is associated with more efficient risk taking and thus improved risk-return trade-offs, a channel for market discipline that has not been emphasized previously in the literature [ABSTRACT FROM AUTHOR]

The high temperature mechanical performance of Al-Si alloys can be enhanced by alloying with transition metals, induced by the formation of thermally stable and coarsening resistant precipitates in the microstructure. However, the binary dispersoids such as Al3Zr can be less effective due to limitations encountered during conventional manufacturing processes. Further improvements can be achieved through the transformation of these binary trialuminides into ternary or quaternary forms by alloying with appropriate elements. The role of transition elements in improving high temperature mechanical properties of Al-Si alloys from both theoretical and practical viewpoints is critically reviewed. [ABSTRACT FROM AUTHOR]

Nanostructured composites of the aluminum 7075 alloy and carbon-coated silver nanoparticles were synthetized by the mechanical milling technique using a high-energy mill SPEX 8000M; the powders generated were compacted, sintered and hot-extruded to produce 1 cm-diameter bars. The composites were then subjected to a wear test using a pin-on-disc device to validate the hypothesis that second phase-ductile nanometric particles homogenously distributed throughout the metalmatrix improve the wear resistance of the material. It was found that silver nanoparticles prevent the wear of the material by acting as an obstacle to dislocations movement during the plastic deformation of the contact surface, as well as a solid lubricant when these are separated from the metal-matrix. [ABSTRACT FROM AUTHOR]

Several rare earth elements are considered by-products to rare earth mining efforts. By using one of these by-product elements in a high-volume application such as aluminum casting alloys, the supply of more valuable rare earths can be globally stabilized. Stabilizing the global rare earth market will decrease the long-term criticality of other rare earth elements. The low demand for Ce, the most abundant rare earth, contributes to the instability of rare earth extraction. In this article, we discuss a series of intermetallic-strengthened Al alloys that exhibit the potential for new high-volume use of Ce. The castability, structure, and mechanical properties of binary, ternary, and quaternary Al-Ce based alloys are discussed. We have determined Al-Ce based alloys to be highly castable across a broad range of compositions. Nanoscale intermetallics dominate the microstructure and are the theorized source of the high ductility. In addition, room-temperature physical properties appear to be competitive with existing aluminum alloys with extended high-temperature stability of the nanostructured intermetallic. [ABSTRACT FROM AUTHOR]

The effects of Lanthanum (La) concentration on the solidification parameters of the α-Al, Al-Si, and Al-Cu phases and on the microstructure, tensile, and hardness properties of eutectic Al-Si-Cu-Mg alloy were systematically investigated. The solidification parameters were examined using computer-aided cooling curve thermal analysis (CA-CCTA). The cooling curve and microstructure analysis showed that La altered the Si structure. The nucleation and growth temperatures of eutectic Si decreased when 0.3 wt.% La was added, and a high depression temperature was obtained with 1.0 wt.% La. High amounts of La considerably modified the Si structure and decreased the area and aspect ratio by 69.9 and 51%, respectively. The thermal analysis result recorded a faster freezing time with the La addition and a 36% alteration in the secondary dendrite arm spacing. Two secondary or ternary La-rich intermetallic phases were formed with needle- and plate-like structures. Furthermore, the mechanical properties were investigated by hardness and tensile tests with different La concentrations. The addition of small amounts of La (0.1 wt.%) significantly improved the ultimate tensile strength and quality index of the Al-Si-Cu-Mg alloy. In addition, the hardness value of Al-11Si-Cu increased by 7-8% with the increasing amount of La added. [ABSTRACT FROM AUTHOR]

The relation between microstructural inhomogeneity and thermal conductivity of a rheocast component manufactured from two different aluminum alloys was investigated. The formation of two different primary α-Al particles was observed and related to multistage solidification process during slurry preparation and die cavity filling process. The microstructural inhomogeneity of the component was quantified as the fraction of α-Al particles in the primary Al phase. A high fraction of coarse solute-lean α-Al particles in the primary Al phase caused a higher thermal conductivity of the component in the near-to-gate region. A variation in thermal conductivity through the rheocast component of 10% was discovered. The effect of an inhomogeneous temperature-dependent thermal conductivity on the thermal performance of a large rheocast heatsink for electronics cooling in an operation environment was studied by means of simulation. Design guidelines were developed to account for the thermal performance of heatsinks with inhomogeneous thermal conductivity, as caused by the rheocasting process. Under the modeling assumptions, the simulation results showed over 2.5% improvement in heatsink thermal resistance when the higher conductivity near-to-gate region was located at the top of the heatsink. Assuming homogeneous thermo-physical properties in a rheocast heatsink may lead to greater than 3.5% error in the estimation of maximum thermal resistance of the heatsink. The variation in thermal conductivity within a large rheocast heatsink was found to be important for obtaining of a robust component design. [ABSTRACT FROM AUTHOR]

Four Al-Si-Mg-Fe alloys with Si contents varying from 1.6 to 4.5 wt pct were rheocast, using the RheoMetal™ process to prepare slurry and cast in a vertical high-pressure die casting machine. Particle size and Si concentration in the α-Al particles in the slurry and in the as-rheocast component were investigated. A uniform distribution of Si in the globular α-Al particles was achieved in the slurry. In the rheocast samples, measurement of the α-Al particles showed that these particles did not increase significantly in size during pouring and secondary solidification. The two additional α-Al particles types, α-Al particles and α-Al particles, were identified as being a result of two discrete nucleation events taking place after slurry production. The Si concentration in the α-Al and α-Al particles indicated that the larger α-Al particles precipitated before the α-Al particles. In addition, in the as-rheocast condition, the Si distribution inside the α-Al particles showed three distinct zones; an unaffected zone, a transition zone, and in some cases the start of a dendritic/cellular zone. The phenomenon of dendritic growth of globular α-Al particles during secondary solidification occurred concomitantly with the final eutectic reaction and increased with increasing amount of the Al-Si eutectic phase. [ABSTRACT FROM AUTHOR]

Superhydrophobic ceria on the aluminum substrate was fabricated, and its corrosion resistance was investigated by different techniques. For example, the so-obtained superhydrophobic sample was immersed into the NaCl aqueous solution, and the variations in the surface wettability as well as the surface morphology were monitored; potentiodynamic polarization in the NaCl aqueous solution was adopted to evaluate its electrochemical corrosion resistance; a droplet of the aqueous solution HCl was dripped onto the superhydrophobic surface, and the corrosion process as well as the surface morphology after corrosion was monitored. The experimental results showed that the superhydrophobic ceria possessed a good corrosion resistance because of the entrapped air in the solid/liquid interface. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Laser surface alloying is one of the recent technologies used in the manufacturing sector for improving the surface properties of the metals. Light weight materials like aluminum alloys, titanium alloys, and magnesium alloys are used in the locomotive, aerospace, and structural applications. In the present work, an experimental study was conducted to improve the surface hardness of commercially pure aluminum plate. CO laser is used to melt pre-placed powders of pure copper, manganese, and magnesium. Microstructure of alloyed surface was analyzed using optical microscope. The best surface alloying was obtained at the optimum values of laser parameters, viz., laser power, scan speed, and laser beam diameter. In the alloyed region, microhardness increased from 30 HV to 430 HV, while it was 60 HV in the heat-affected region. Tensile tests revealed some reduction in the strength and total elongation due to alloying. On the other hand, corrosion resistance improved. [ABSTRACT FROM AUTHOR]

Mechanical properties of a 2024 aluminium alloy laminated structure produced by the ultrasonic consolidation were investigated. In comparison with the monolithic aluminium alloy, the existence of laminated structure gave different fatigue and fracture mechanisms that associated with the layer interfaces. The Al/Al laminated specimens had the lower tensile strength but much higher fracture toughness than the monolithic Al specimens due to the exit of interface delaminations around the crack tip. The fatigue life of the laminated specimens was comparable to that of the monolithic Al specimens, though the initiation and propagation of the crack in the laminated specimens depended strongly on the microstructure of each material. The interface between layers could arrest the fatigue crack and impede the further propagation. [ABSTRACT FROM AUTHOR]

Copyright of Archives of Metallurgy & Materials is the property of Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A study is made of the effect of the T6 heat treatment on the mechanical properties (strength, hardness, elongation, impact toughness) of aluminum alloy AlSi12CuNiMg modified with master alloy Al - 10% Sr. Differential thermal analysis is used to obtain curves that describe the heating of the alloy before it melts. The regimes that are optimum for solution treatment and aging of the alloy are determined. [ABSTRACT FROM AUTHOR]

In the context of a universal search for alternatives to chromate-based coatings, which are toxic for both human beings and the environment, a multilayer coating for Al protection purposes is developed and investigated in the current work. The first layer is selected to be a hexamethyldisiloxane-based plasma polymer film (PPF), deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD), due to a number of interesting features that are characteristic of plasma polymers. The second layer is synthesized via the polymerization of the 2-ethylhexyl acrylate monomer initiated from the free radicals trapped on the surface of the PPF during its growth. A subsequent layer of a copolymer of 2-ethylhexyl acrylate and glycidyl methacrylate, poly(EHA-co-GMA), is deposited by spin coating to increase the corrosion resistance of the coating. An improvement in the anti-corrosion properties of the multilayer coating by approximately three orders of magnitude as compared to the uncoated Al substrate is observed. Further enhancement of the adhesion and scratch resistance properties is addressed via UV-crosslinking and the incorporation of in situ generated silica nanoparticles into the final layer. [ABSTRACT FROM AUTHOR]

Copyright of Archives of Metallurgy & Materials is the property of Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Crack growth of aluminum alloy 5083 was investigated when subjected to the in-plane biaxial tension-tension fatigue with stress ratio of 0.5 under ambient laboratory and saltwater environments. Cruciform specimens with a center hole, containing a notch and precrack at 45° to the specimen's arms, were tested in a biaxial fatigue test machine. Two biaxiality ratios, λ = 1 and λ = 1.5, were studied. For λ = 1, crack propagated along a straight line collinearly with the precrack, while for λ = 1.5 case, the crack path was curved and non-collinear with the precrack. Uniaxial fatigue tests were also conducted. Crack growth rates were faster under the biaxiality fatigue in comparison to uniaxial fatigue at a given crack driving force (Δ K or Δ G) in both environments. Further, an increase in biaxiality ratio increased the crack growth rate, i.e., faster for λ = 1.5 case than λ = 1 case. Both biaxial fatigue and saltwater environment showed detrimental effects on the fatigue crack growth resistance of 5083, and its combination is highly detrimental when compared to uniaxial fatigue. [ABSTRACT FROM AUTHOR]

Al-Si-Mg-based secondary cast alloys are attractive candidates for thin-walled high-pressure die castings for applications in the transport industry. The present study investigates the effect of manganese additions at high cooling rates on microstructure, mechanical properties, and on the dominating fracture mechanisms of alloy AlSi10Mg with an elevated iron concentration. Systematic variations of the Mn content from 0.20 to 0.85 wt pct at a constant Fe content of 0.55 wt pct illustrate the key changes in type, phase fraction, and shape of the Fe-containing intermetallic phases, and the corresponding influence on the alloy's ductility. For high-pressure die casting (HPDC), an optimal range of the Mn content between 0.40 and 0.60 wt pct, equivalent to a Mn/Fe ratio of approximately 1, has been identified. At these Mn and Fe contents, the high cooling rates obtained in HPDC result in the formation of fine and homogeneously distributed α-Al(Fe,Mn)Si phase, and crack initiation is transferred from AlFeSi intermetallics to eutectic silicon. The study interprets the microstructure-property relationship in the light of thermodynamic calculations which reveal a significant increase in undercooling of the α-Al(Fe,Mn)Si phase with increased Mn content. It concludes that the interdependence of the well-defined Mn/Fe ratio and the high cooling rate in HPDC can generate superior ductility in secondary AlSi10Mg cast alloys. [ABSTRACT FROM AUTHOR]

The purpose of this research was to develop and pilot test an intervention to optimize functional recovery for breast cancer survivors. Over two studies, 31 women enrolled in a goal-setting program via telephone. All eligible women enrolled (37% of those screened) and 66% completed all study activities. Completers were highly satisfied with the intervention, using it to address, on average, four different challenging activities. The longitudinal analysis showed a main effect of time for overall quality of life (F(5, 43.1) = 5.1,p= 0.001) and improvements in active coping (F(3, 31.7) = 4.9,p= 0.007), planning (F(3, 36.0) = 4.1,p= 0.01), reframing (F(3, 29.3) = 8.5,p< 0.001), and decreases in self-blame (F(3,31.6) = 4.3,p= 0.01). The intervention is feasible and warrants further study to determine its efficacy in fostering recovery and maximizing activity engagement after cancer treatment. [ABSTRACT FROM PUBLISHER]

In this research, 3-mm-thick AA3003-H18 non-heat-treatable aluminum alloy plates were joined by friction stir welding (FSW). It was performed by adding pure Cu and premixed Cu-Al powders at various rotational speeds of 800, 1000, and 1200 rpm and constant traveling speeds of 100 mm/min. At first, the powder was filled into the gap (0.2 or 0.4 mm) between two aluminum alloy plates, and then the FSW process was performed in two passes. The microstructure, mechanical properties, and formation of intermetallic compounds were investigated in both cases of using pure Cu and premixed Al-Cu powders. The results of using pure Cu and premixed Al-Cu powders were compared in the stir zone at various rotational speeds. The copper particle distribution and formation of Al-Cu intermetallic compounds (AlCu and AlCu) in the stir zone were desirable using premixed Al-Cu powder into the gap. The hardness values were significantly increased by formation of Al-Cu intermetallic compounds in the stir zone and it was uniform throughout the stir zone when premixed Al-Cu powder was used. Also, longitudinal tensile strength from the stir zone was higher when premixed Al-Cu powder was used instead of pure Cu powder. [ABSTRACT FROM AUTHOR]