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The results of the pressure testing of mechanical properties of single crystals of pure tungsten and low-alloyed alloys W–2Re and W–1Re–1Mo (wt%) with a crystallographic orientation 〈100〉 which were prepared by plasma-arc melting are summarized. The effect of alloying and the deformation rate on these properties have also been investigated and the fracture surfaces of the individual single crystals have been evaluated with the aid of the photometric method. The differences in the deformation behavior of pure tungsten and W–Re and W–1Mo–Re alloys were observed, which relate to the particularities of rhenium and molybdenum action in the tungsten solid solution. It can be seen from the observed results that tungsten alloying with low rhenium and molybdenum contents decreased all mechanical properties when applying the deformation rate of 0.2 mm/min. The biggest decrease was observed for the offset yield strength value. When testing with the deformation rate of 2 mm/min, the strength limit of the W–2Re alloy increased to 2013 MPa, while R pt0.2 decreased by 33% in comparison with the pure tungsten single crystal. However, the ε r value remained at the same level ∼30%. In the W–1Re–1Mo single crystal, the R pt0.2 and R mt values decreased, while ε r increased slightly. [ABSTRACT FROM AUTHOR]

International Standard ISO 6892-2 maintains that the strain rate variations and test temperature variations can induce the measurement uncertainty of mechanical properties in tensile testing, which will imperil the reliability of tension tests. In this paper, the measurement uncertainty of reduction in area is first described experimentally. Second, the fundamental results on the microscopic theory of elastic deformation in metals were briefly mentioned. Then the measurement uncertainty is clarified based on this theory. It is shown that the elastic deformation of tension test induces the segregation of impurities to grain boundaries and the relevant embrittlement which produces the measurement uncertainty of reduction in area in tensile testing. This work gives a theoretical basis for correcting the present tension testing system to avoid the measurement uncertainty of reduction in area. [ABSTRACT FROM AUTHOR]

Accurate prediction of the mechanical properties in quenched steel parts has been considered by many recent researchers. For this purpose, different methods have been introduced. One of them is the quench factor analysis (QFA) which is based on continuous cooling rate during quenching. Another method for prediction of the mechanical properties in heat-treated alloys is artificial neural networks (ANNs). In the present research, QFA and ANN approaches have been used to predict the hardness of quenched steel parts in several different quench media. Then for the two methods, the predicted values have been compared with the experimental data. Results showed that the two methods are suitable in prediction of the hardness at different points of the quenched steel parts. [ABSTRACT FROM AUTHOR]

A new activated carbon (AC), prepared by carbonization and chemical activation of crushed pine needles, was characterized and examined for its potential in removing two heavy metals, namely Nickel (Ni) and Cadmium (Cd). Fixed-bed column testing procedure was adopted in the study. Depending on the individual metal tested, different initial solution pH values and different initial metal concentrations were used to evaluate their impacts on the AC adsorption process. Breakthrough curves were used to assess the adsorption capacities. Batch reaction tests were also conducted and the resulting data were fitted to adsorption isotherms. Furthermore tests were conducted where the two metals were combined in the test samples so as to determine their synergistic effect. The results indicated that the highest metal removals and adsorption capacities were attained at the highest pH values and concentrations tested for each of the two metals. Also, the results recorded for the batch experiments exhibited higher capacities than those recorded for the column tests and the resulting data fitted best the Freundlich isotherm. The results of the binary tests showed that the AC adsorption capacity of the individual metals was not affected. [ABSTRACT FROM AUTHOR]

Metal hyperaccumulation may be an elemental defense, in which high concentrations of a metal in plant tissues decrease herbivore survival or growth rate. The Joint Effects Hypothesis suggests that a combination of metals, or a combination of a metal with an organic compound, may have an enhanced defensive effect. The enhancement may be additive or synergistic: in either case the concentration of a particular metal necessary to provide a defensive benefit for the plant is lowered. We tested the Joint Effects Hypothesis using Spodoptera exigua (beet armyworm) neonates fed artificial diets. Metal + metal experiments utilized diets amended with metal pairs, using four metals commonly hyperaccumulated by plants (Co, Cu, Ni, and Zn). We also conducted metal + organic compound experiments, pairing each metal with nicotine, mustard seed powder, or tannic acid. We tested for joint effects using both lethal (LC levels) and sublethal concentrations (10-25 % reduced larval weight) of the chemicals tested. For all experiments, either additive or synergistic effects were found. Of the metal + metal pairs tested, three (Co + Cu, Cu + Zn, and Ni + Zn) were synergistic in lethal concentration tests and only Co + Cu was synergistic in sublethal tests. For metal + organic combination lethal tests, synergism occurred for all combinations except for Co or Ni + nicotine, Ni + mustard seed powder, and Zn + nicotine. For sublethal tests, Zn + all three organic chemicals, Co + mustard seed powder or tannic acid, and Cu + nicotine, were synergistic. These results support the Joint Effects Hypothesis, suggesting that metals combined with other metals or organic compounds may be more effective against herbivores than individual metals. [ABSTRACT FROM AUTHOR]

During maintenance, a post-World War II military training airplane experienced a ground fire that resulted in damage to the lower fuselage forward of the wing spar carry-through structure. Although the fire was contained approximately 18 in. forward of the carry-through structure, existing airworthiness concerns and the critical nature of this area resulted in the need to evaluate the possibility of damage resulting from the fire. A correlation between the electrical conductivity and mechanical properties of the aluminum structure was established from components that were fire damaged and, consequently, removed during repair of the aircraft. This correlation was then used to non-destructively evaluate the integrity of the material in the carry-through structure and, ultimately, confirmed that the carry-through structure did not have to be replaced. [ABSTRACT FROM AUTHOR]

Corrosion testing was conducted in a superheated geothermal steam from the IDDP-1 well in Iceland at 360 °C for 113 days. Severe silica scaling occurred in the test. The average corrosion rate was extremely low; less than 0.1 mm/year for all the metals tested which can be explained by the combined protective effect of the silica and the high superheat in the steam preventing any condensation. Despite the low average corrosion rate, the microstructural analysis show that even the most corrosion resistant materials tested, such as UNS N06625 and titanium UNS R52400 show localized corrosion damage after the test. Only the low alloy stainless steels UNS S30403, UNS 31603 and UNS 31803 showed evidence of Stress Corrosion Cracking. [ABSTRACT FROM AUTHOR]

An approximate permanent strain of 0.3% was generated in Ce-TZP/alumina nanocomposite during static fatigue tests carried out at room temperature under ≈800 MPa for up to 10 6 s. For the deformed specimens, changes in the crystalline phase, ferroelastic domain orientation, and residual stresses were investigated. No evidence to support crystalline orientation due to ferroelasticity was observed. The monoclinic content of the deformed surface was determined to be 27 and 17 vol% by using small-area XRD and Raman spectroscopy, respectively. The estimated and experimental strains corresponding to the transformed monoclinic content were roughly in good agreement. A fairly high transformation zone and compressive residual stresses were observed up to 100 μm depth from the surface. Generated permanent strain and residual stresses disappeared completely upon annealing at 1100 °C. The obtained results revealed plastic deformation to be principally attributable to volume dilatation caused by t–m transformation and that it developed with residual strains. [ABSTRACT FROM AUTHOR]

In this paper, measurement and analysis of both metal magnetic memory (MMM) signals and yield strain were performed on six defect-free 20g base metal specimens to explore the relationship between magnetic distortion and yield. The change laws of both MMM signals and local point yielding were studied, respectively, by the MMM technique and electrometric method during the whole period of static tensile testing. The results show that MMM signal distortion only occurs at the yielding point, which is the typical characteristic of MMM signals in the yield phase. Yield strain is obviously uneven at the yielding point and residual strain or plastic strain remains after unloading. There is a one-to-one correspondence between the occurrence times and locations of MMM signal distortion and yield. Magnetic distortion is related directly to residual strain, which is the basic reason for the occurrence of magnetic distortion; the larger the residual strain, the more serious the magnetic distortion. The MMM method has a special efficiency to detect local point yielding, which has great significance for solving the engineering problem of local yield. [ABSTRACT FROM AUTHOR]

A stress-strain curve is generally measured by tensile testing or compression testing. In some metal forming processes, the maximum strain exceeds 5.0 (500%); however, the standard testing methods can only measure an stress-strain curve up to a strain of 1.0. Therefore, a new method was developed that enables us to measure a stress-strain curve for strains up to 10.0. High-pressure torsion was applied for the measurement. Using high-pressure torsion, it is possible to introduce larger strains than conventional methods. A stress-strain curve measurement was performed for pure aluminum. The stress-strain curve measured using the developed method was compared with that obtained using a compression test. It is confirmed that the flow stress was successfully measured up to a strain of 10.0. In addition, the results for the developed method correspond with that of the compression test up to a strain of 1.0. [ABSTRACT FROM AUTHOR]

The effect of bis-(2-ethylhexyl)phosphoric acid (DEHPA) on the region of existence, conductivity and structure of sodium bis-(2-ethylhexyl)phosphate (NaDEHP) microemulsion has a dual nature and depends on DEHPA concentration. In the system NaDEHP-DEHPA-kerosene-water, the narrowing of the microemulsion region is observed with DEHPA concentration in the organic phase growth from 0.1 to 0.5 mol/L. The increase of DEHPA concentration in the organic phase from 0.1 to 0.4 mol/L leads to the reduction of electrical conductivity of the microemulsions. Based on the conductivity and viscosity measurements, we suppose the transition from reverse microemulsion with isolated droplets to percolate microemulsion at volume fraction of water 0.18 ( $$W = C_{{H_{2} O}} /C_{\text{NaDEHP}}$$ = 8). Droplet size of the microemulsions increases linearly with W growth. The rise of DEHPA concentration in the organic phase from 0.1 to 0.3 mol/L causes the growth of the coefficient at W in the equation d = kW + b from 0.038 to 0.249, i.e., it increases the slope of the lines. In contrast, DEHPA introduction at the concentration 0.1 mol/L (in the organic phase) leads to the expansion of the microemulsion region, does not affect the conductivity and decreases the coefficient at W. The rate of copper recovery into the microemulsion increases considerably with the rise of DEHPA concentration from 0.0 to 0.3 mol/L; no dual effect is observed. The following composition of the microemulsion for non-ferrous metals leaching is recommended: C = 1.6 mol/L, C = 0.3 mol/L (in the organic phase); W = 8-32. [ABSTRACT FROM AUTHOR]

Lactoferrin is a minor whey protein known for its multifunctionalities, particularly for its rule in regulation of immune system and for its antimicrobial activities. Although bovine lactoferrin has been extensively studied, very few information exists on lactoferrin from mare's milk. This article studies the antioxidant properties via metal chelation of purified lactoferrin from Kazakhstan mare's milk. Equine lactoferrin shows free radical-scavenger activity when tested with radical DPPH and ABTS and has reducing capacities testing by FRAP. Moreover, the ferrous(II) and copper(II) ion-chelating power is highlighted by chemical colorimetric tests. Finally, the newly introduced biophysics switchSENSE® technology allowed to measure in real time the molecular interactions between equine lactoferrin and divalent cations. The order of magnitude of the K D values was tens or so μM for the four metal ions tested: Zn2+ (K D = 23.9 ± 4.0 μM), Ca2+ (K D = 28.2 ± 4.4 μM), Cu2+ (K D = 43.5 ± 5.1 μM) and Fe2+ (K D = 54.1 ± 8.9 μM). According to these results, we can conclude that equine lactoferrin shows antioxidant activity by radical-scavenging mechanism, reducing capacities and divalent pro-oxidant metals chelation ability. • Purification of equine lactoferrin, which we purified from Kazakh mare's milk. • Antioxidant activity of equine lactoferrin. • Using complementary approach: radical-scavenging, metal reducing and divalent pro-oxidant metal chelation activities. • Using new biophysics switchSENSE® technology to measure in real time the molecular interactions between two partners. • Determination of association, dissociation and equilibrium constants of the complex metal-lactoferrin. [ABSTRACT FROM AUTHOR]

The hydraulic bulge test (HBT) is an important experimental technique to identify the properties of materials and, in particular, metals. One of the main advantages of such technique, in testing metals, is the possibility of reaching high levels of deformation before fracture. Moreover it allows the investigation of a biaxial loading condition. A hemispherical test can be performed using mechanical punches or the hydraulic pressure of a fluid. When hydraulic pressure is used, the test is not affected by friction. The hydraulic bulge test (HBT) is therefore a very efficient method to evaluate the properties of metals at large strains. Usually, the outcome of the HBT is the hardening curve in the equi-biaxial stress state that occurs at the top of the dome, during the expansion. In this paper a different approach is proposed, where the full-field displacement field obtained with stereo-DIC is used in an inverse identification scheme. The finite strain theory is used to map the stress and strain in the reference configuration so that the problem can be reduced to a 2D plane stress case. The method was first validated using a numerical model of the HBT and then applied on a real test performed on a BH340 steel. [ABSTRACT FROM AUTHOR]

• Portable capillary electrophoresis instrument for field detection of heavy metals. • Size of 21 cm x 10 cm x 7 cm, powered from the USB port of a laptop computer, at a cost of ∼$1200 USD. • Instrument based on peristaltic pumps, with hydrodynamic injection performed at defined points in the pump cycle. • Heavy metals detected by complexation with 4-(2-Pyridylazo) resorcinol. • Limits of detection for Co(II), Cu(II) and Zn(II) were 0.46, 1.14, 0.58 µM, respectively. A compact, inexpensive capillary electrophoresis instrument was developed for monitoring metal ions and evaluated for Zn(II) in remote contaminated locations in western Tasmania, Australia. The portable instrument, measuring 21 cm x 10 cm x 7 cm, was powered from the USB port of a laptop computer and built from off-the-shelf components costing ∼$1200 USD. Electrophoretic separations were conducted using a fused silica capillary (10–50 µm I.D.), applying 8.5 kV over capillaries ranging from 25 cm to 40 cm in length. The capillary inlet was connected with an electrically grounded cross-piece as flow-through injection interface. Automated fluidic management was achieved by controlling four mini peristaltic pumps and a solenoid valve. Detection was realised using a purpose-built visible LED absorption detector, optimised for the detection of Co(II), Cu(II) and Zn(II) after complexation with 4-(2-Pyridylazo) resorcinol (PAR). Limits of detection of sub-µM were obtained. The instrument was tested for continuous operation in the laboratory for up to 3 months, and relative standard deviations of <5.4% were found over 945 consecutive injections. In the field, the system was able to measure 106 samples within 11 h, the time it can be powered from the laptop computer. As Field measurement of Zn(II) in western Tasmania was demonstrated to show capability for on-site metal testing. [ABSTRACT FROM AUTHOR]

The article presents the discussion on Plastornetrex securing an Innovate UK Smart Grant for developing in-field metal testing technologies. Topics include developing new industry-changing products enabling rapid and accurate testing of metal components in the field; and reducing catastrophic failures leading to massive environmental damage.

A technique has been developed for determining coefficients in the power approximation of the “stress–strain” diagram by results of scratch testing with a Berkovich indenter under a normal load of 5 mN on the indenter. The procedure is based on a comparison of experimental results with the finite element simulation of the test process. The technique is intended for application on nanomechanical testing equipment enabling one to perform tests with recording of loading diagrams in terms of the “normal force – indenter displacement” coordinates. To obtain correct results, one must observe the following restrictions: indenter penetration depth > 150 nm under a loading of 5 mN with the indenter tip curvature radius R < 50 nm; indenter penetration depth > 250 nm with 50 < R < 100 nm; the tested metal must be ductile enough, for a scratch to be formed by the mechanism of plastic deformation rather than fracture. [ABSTRACT FROM PUBLISHER]

In this work, we approach the possibilities of infrared thermography for non-destructive testing of metallic materials. We show that the passive alternative of the method makes it possible to improve detection of surface defects existing in deep-drawn parts and visible to the naked eye. We then show that active infrared thermography, in particular coupled with induction excitation, can replace in certain cases the magnetic particle inspection, allowing the detection of very fine defects in forged parts. Finally, the study of a stepped block confirms the possibilities of active infrared thermography to detect defects not open to the surface and underlying defects. [ABSTRACT FROM AUTHOR]

In recent times, metal-free chemistry has received significant attention due to its inherent qualities and its potential savings in the costs of (i) reagents and (ii) environmental treatments of residues. In this context, recently developed neutral organic electron-donors have shown an ability to perform challenging reductions that are traditionally the preserve of reactive metals and metal-based complexes, under mild reaction conditions. Hence, this feature article is aimed at describing the evolution of neutral organic super-electron-donors and their rapidly developing applications in electron-transfer reactions. [ABSTRACT FROM AUTHOR]

One major problem in ultrasonic NDT for steel products and welding inspection is that standard linear methods are often unable to distinguish the nature of signals. Partially recrystallized grains, voids, small cracks or inclusions in the piece under investigation could produce indications very similar in terms of acoustic energy reflected and ultrasonic peaks envelope. Here, we analyze the nonlinear response to ultrasonic excitations of steel bars with both kind of imperfections purposefully generated. Using the Scaling Subtraction Method as a tool for the analysis, we show differences in the nonlinear signature, which can be used to distinguish nondestructively a crack/delamination from a region with imperfect grains formation, with possible applications of this technique in the production cycle. [ABSTRACT FROM AUTHOR]

Highlights: [•] MMC using cemented carbide scrap, which is a cost efficient hard phase alternative, can be produced by casting. [•] Using optimised casting parameters dissolution of cemented carbide scrap is low and bonding with the matrix is good. [•] Optimised parameters involve that cemented carbide scrap is as short as possible in the liquid melt, still good flux of the melt must be guaranteed. [•] Abrasive wear tests show excellent performance of MMCs with cemented carbide scrap. [•] The investigated MMCs are competitive to expensive wear protection solutions in abrasive environment also at 500°C testing temperature. [ABSTRACT FROM AUTHOR]

Electrochemical corrosion behavior of a thermal-sprayed Al-Si coated Q235 steel has been investigated in simulated soil solutions. The as-received Q235 steel and galvanized steel for grounding grids were also examined for comparison purpose. The effects of pH value of testing solutions have been examined. The thermal-sprayed Al-Si coated steel showed better corrosion resistance in acidic and neutral solutions than the as-received Q235 steel and galvanized steel, having the largest polarization resistance, the lowest anodic current density, and the largest film resistance. However, in strong alkaline solution, the corrosion resistance of the thermal-sprayed Al-Si coated steel degraded rapidly due to the change of corrosion product scale. Related corrosion mechanisms are also discussed. [ABSTRACT FROM AUTHOR]

Stainless steels employed for manufacturing automotive exhaust systems must withstand severe thermal cycles, corrosive environment due to urea decomposition, and welding operations. AISI 409 ferritic stainless steel can be considered a low-cost alternative for this application. However, depending on the manufacturing conditions during welding cycles, this material can be sensitized due to the precipitation of chromium carbides at grain boundaries. In this work, the intergranular corrosion resistances of the AISI 409 ferritic stainless steel were evaluated after annealing at 300, 500, and 700 °C for 2, 4, and 6 h. Solution-annealed samples were also tested for comparison purposes. Two methodologies were used to assess the sensitization behavior of the 409 stainless steel samples: the first one was based on the ASTM A763 (practice W), while the second one was based on the double-loop electrochemical potentiodynamic reactivation test. It was possible to identify that the annealing treatment performed at 500 °C was more critical to the occurrence of intergranular corrosion. [ABSTRACT FROM AUTHOR]

The anisotropic coefficients of Hill's yield criterion are determined through a novel genetic algorithms-based multi-objective optimization approach. The classical method of determining anisotropic coefficients is sensitive to the effective plastic strain. In the present procedure, that limitation is overcome using a genetically evolved meta-model of the entire stress strain curve, obtained from uniaxial tension tests conducted in the rolling direction and transverse directions, and biaxial tension. Then, an effective strain that causes the least error in terms of two theoretically derived objective functions is chosen. The anisotropic constants evolved through genetic algorithms correlate very well with the classical results. This approach is expected to be successful for more complex constitutive equations as well. [ABSTRACT FROM AUTHOR]

This study investigates the effect of titanium and nitrogen elements on the microstructures and wear behaviors of medium carbon Fe-B cast alloy. The as-cast microstructures of Fe-B cast alloy consist of the eutectic boride, pearlite, and ferrite. Moreover, the as-cast eutectic boride structures are greatly refined when titanium and nitrogen are added. The boride area fraction, average boride area, Rockwell hardness, etc., are also investigated systemically. The wear behaviors of medium carbon Fe-B cast alloy are studied by a three-body abrasive wear tester. The results show that the wear weight loss of Fe-B cast alloy with titanium and nitrogen elements is lower than that of the ordinary Fe-B cast alloy. Meanwhile, the wear mechanism of Fe-B cast alloy with different titanium and nitrogen concentrations is described and analyzed. [ABSTRACT FROM AUTHOR]

In the present study, cold spraying technique was used to fabricate a metal matrix composite (MMC) that consists of Ni matrix and 20 vol.% NiAl particles at two different particle sizes as reinforcement. This study intends to investigate the effect of reinforcement particle size on microstructural and mechanical properties of cold sprayed MMCs. Two different NiAl powders with nominal particle size of −45 to +5 and +45 to 100 μm were used as reinforcement in this study. Cold sprayed Ni-NiAl samples were subjected to the microstructural observation and characterization prior to any mechanical testing. Then, samples were tested using nano-indentation, Knoop hardness, Vickers hardness, and Resonance frequency to evaluate their mechanical properties. No significant changes were observed in microstructural characteristics due to different particle sizes. The results obtained from a variety of mechanical testings indicated that the increasing reinforcement particle size resulted in the slight reduction of mechanical properties such as elastic modulus and hardness in cold sprayed MMCs. The mechanical interlock between deposited particles defines the bonding strength in cold sprayed samples. Small size particles have a higher velocity and impact resulting in stronger interlock between deformed particles. [ABSTRACT FROM AUTHOR]