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In this study, we have reported the structural and mechanical properties of B-doped ZnO (Zn 1-x B x O, x = 0.00, 0.05, 0.07, 0.09, 0.11) by using XRD, SEM, EDS and static Vickers micro-hardness measurements. All nanopowder samples were prepared by hydrothermal method. From the XRD measurements, we have found that all the samples crystalize in hexagonal wurtzite structure and crystallite sizes were found to be 61.50, 36.97, 36.65, 36.59 and 34.85 nm for x = 0.00, 0.05, 0.07, 0.09, 0.11 samples, respectively. From the SEM measurements, the irregular appearance and size distribution of the particles were observed for all samples. The chemical composition of Zn 1-x B x O nanopowders were investigated by EDX spectroscopy. Zn,O and B peaks are clearly seen and the content of Zn, O and B are consistent with preparation of samples. From the load dependent indentation diagonal length measurements, load dependent (apparent) hardness, elastic modulus, yield strength, and fracture toughness values of the samples were computed. The hardness values increase with increasing the boron content and the applied load. In addition, the apparent hardness values were analyzed by using the various theoretical models to evaluate the load independent (true) hardness values. The IIC model was found to be sufficient for our investigations. The possible reasons for the observed changes in mechanical, structural properties due to B-doping in ZnO were discussed. • B-doped ZnO nanopowders are synthesized by hydrothermal method. • All samples are polycrystalline with a hexagonal-wurtzite structure. • We tried to analyze the microhardness data using various models. • The hardnesses increase with increasing the boron content and the applied load. • The IIC model was found to be sufficient for our investigations. [ABSTRACT FROM AUTHOR]

Isochronal annealing of deformed commercial iron samples (99.88 m.-% Fe) after cold deformation is studied by means of Vickers microhardness and physical techniques based on positron annihilation (positron annihilation lifetime spectroscopy (PALS) and Doppler broadening of the annihilation radiation (DBAR)). Undeformed Fe with a purity of 99.998 m.-% was used as a reference material to compare it with the used commercial Fe. Additionally, EBSD (electron backscatterded diffraction) was used to estimate the recrystallization fraction in the samples. In the temperature range 600–1000 °C the recrystallization phenomenon can be followed with these techniques and similar results are obtained, while in the temperature range 20–600 °C the recovery process has to be included and the results for positron annihilation lifetime presented a deviation due to its sensitiveness for changes in point defect configurations. [ABSTRACT FROM AUTHOR]

Vickers microhardness measurements of Y 3−x Nd x Ba 5−x Ca x Cu 8 O 18−δ samples, 0.00 ≤ x ≤ 0.40, were carried out at room temperature at different applied loads varies from 0.25 N to 10.00 N. Vickers microhardness decreases as the substitution content increases, as well as it decreases as the applied loads increase. The results were analyzed using different models such as Meyer's law, Hays–Kendall (HK) approach, elastic/plastic deformation (EPD) model, proportional specimen resistance (PSR) model and modified proportional specimen resistance (MPSR) model. The analysis shows that the MPSR model is the most suitable one to describe the load independent microhardness for Y 3−x Nd x Ba 5−x Ca x Cu 8 O 18−δ superconducting samples at high load. Some important mechanical parameters such as Young's modulus ( E ), yield strength ( Y ), fracture toughness ( K f ) and brittleness index ( B i ) were calculated as a function of substitution content. The results show that they decrease by increasing the substation content for Y 3−x Nd x Ba 5−x Ca x Cu 8 O 18−δ samples. [ABSTRACT FROM AUTHOR]

Mechanically alloyed amorphous Al 76 Ni 8 Ti 8 Zr 4 Y 4 (at.%) alloy powder was consolidated by high-pressure sintering process. The influence of the consolidation temperature on the structure and mechanical properties of the consolidated bulk alloys was examined by X-ray diffraction (XRD), Optical microscopy (OM), Scanning electron microscopy (SEM), Vickers Hardness Tester and Nano Indenter. Structural investigations of the bulk materials revealed that most of the amorphous structure was retained after consolidation at 623 K, however, compaction at 723 K and 823 K caused crystallization of the amorphous phase with the appearance of white regions. The results also indicate that application of high pressure affected the crystallization products of the present alloy. Micro mechanical analysis showed that the microhardness of the bulk composites increased from 945HV 0.1 to 1177HV 0.1 with the consolidation temperature increasing. The evolution trends of nanohardness and Young’s modulus agree well with the Vickers hardness testing results, indentation size effect (ISE) is observed in the multicomponent alloy systems. The yield strength, Meyer exponent and the indentation impressions of these bulk alloys have also been compared. [ABSTRACT FROM AUTHOR]

Highlights: [•] The effect of nanosized ZnFe2O4 on the Gd-123 phase was studied. [•] The phase formation and superconducting parameters were improved up to x =0.06wt.%. [•] The Vickers microhardness number increased as x increased. [•] The Vickers microhardness data agreed with the proportional specimen resistance model. [ABSTRACT FROM AUTHOR]

Highlights: [•] Single- and four-core MgB2 wires have been manufactured by internal magnesium diffusion (IMD) into boron. [•] High density of MgB2 was evaluated by micro-hardness measurements. [•] The critical current densities of IMD wires are 17 times higher in comparison to those made by powder-in-tube process. [•] High current densities of IMD wires are promising for practical applications of MgB2. [ABSTRACT FROM AUTHOR]

Highlights: [•] Al75V12.5Fe12.5 − x Cu x (x =0, 6.25, and 12.5 at%) amorphous powders were synthesized by MA. [•] Bulk Al75V12.5Fe12.5 amorphous alloy is obtained by means of hydraulic pressing. [•] The Vickers microhardness of bulk sample is in the range of 821-927 HV. [ABSTRACT FROM AUTHOR]

Highlights: [•] The 98.5% relative density W–5wt% Cr alloy was fabricated by SPS method. [•] The Vickers hardness of the annealed samples can reach 760Hv. [•] Obtained nano-scaled microstructure may be beneficial for irradiation resistance of W-based alloy. [Copyright &y& Elsevier]

Abstract: The artificial aging of an AlMgSi commercial alloy was studied by electrical resistometry measurements. A laboratory-made experimental arrangement was designed in order to avoid natural aging prior to artificial aging. The electrical resistometry evolution was compared to Vickers microhardness determinations, and correlated with the precipitation sequence. The temporal evolution of β″ relative volume fraction is described by a normalized resistance evolution by means of a Johnson–Mehl–Avrami type equation. The activation energy is in good agreement with that obtained from differential scanning calorimetric experiments. [Copyright &y& Elsevier]

Abstract: Quantitative Vickers microhardnesses for α+δ′-, δ′-, δ-, δ+ɛ- and ɛ-phase hafnium hydrides (HfH x ; 1.46≤ x ≤2.02) and deuterides (HfD x ; 1.55≤ x ≤1.94) at room temperature have been measured using a Vickers hardness tester. The Vickers microhardnesses of the HfH x and HfD x gradually decreased with an increase of the hydrogen concentration, and those for 1.46≤ x ≤1.70 were higher than that of α-phase metallic Hf. It was revealed by a first-principles calculation as well as an X-ray photoelectron spectroscopy (XPS) measurement that the hydrogen concentration dependence of the microhardnesses for HfH x and HfD x was ascribed mainly in terms of its influence on charge transfer from Hf 5d to H 1s and reduction of cohesive energy. [Copyright &y& Elsevier]

Abstract: LEAlB14 (orthorhombic, Imam) (LE=Li, Mg) crystals were grown using metal salts (Li2CO3, LiF, LiI, MgO, MgF2, MgI2) and crystalline boron from a high-temperature aluminium metal flux. The growth conditions for growing LEAlB14 were established using the starting mixtures of B/LE=2.0, and Al metal was added to each mixture at a mass ratio of 1:15–20. LEAlB14 crystals from the Al-self flux using metal salts could be obtained from all the different salts. The maximum dimensions of LiAlB14 and MgAlB14 crystals were approximately 18 and 12mm for the crystals obtained from LiF and MgF2. The unit-cell parameters of as-grown LEAlB14 are as follows: for LiAlB14, obtained from LiF, a =0.5846 (2) nm, b =0.8144 (2) nm, c =1.0355 (3) nm, V =0.4930 (2) nm3: for MgAlB14, obtained from MgF2, a =0.5845 (2) nm, b =0.8114 (2) nm, c =1.0330 (3) nm, V =0.4899 (3) nm3. Microhardness, oxidation resistance and magnetic susceptibility of these materials are described in detail. [Copyright &y& Elsevier]

Abstract: Al1.1Be0.7B22, Al1.4Mg0.45B22, Al x Cu y B105 (x =2.8–3.3, y =2.9–1.0), Al1.3Cu1.1B25 and CuB23 crystals were grown from high-temperature melts of the systems Al–M–B (M=Be, Mg, Cu) and Cu–B in an argon atmosphere. The maximum dimensions of Al1.1Be0.7B22, Al1.4Mg0.45B22, Al3.1Cu2.0B105 and Al1.3Cu1.1B25 crystals were obtained in the ranges of approximately 2.5–5.2mm. CuB23 crystals prepared had maximum dimensions of approximately 30μm. The Al1.1Be0.7B22 and Al1.4Mg0.45B22 crystals were obtained as plate-like crystals having well-developed {101} and {001} faces, and Al3.1Cu2.0B105 and Al1.3Cu1.1B25 crystals were obtained in the form of needle or rhombohedral plate as bounded by {001} faces and grew as prismatic shape extending in the c direction. The values of Vickers microhardness on relatively large {101}, {100}, {001} and {001} faces of Al1.1Be0.7B22, Al1.4Mg0.45B22, Al x Cu y B105 (x =2.8–3.3, y =2.9–1.0) and Al1.3Cu1.1B25 crystals are in the ranges of 25.4 (0.5) to 27.8 (1.7)GPa. Anomalous magnetic behavior was not observed for any of the compounds, and the good agreement of the temperature independent susceptibility for the Al x Cu y B105 compounds with different ratio of metal elements indicate the non-metallic nature of this phase. [Copyright &y& Elsevier]

Microstructure and microhardness evolution of a metastable Ti-10V-2Fe-3Al (Ti-1023) alloy were systematically investigated under uniaxial tension (UT), single torsion (ST), and simultaneous tension-torsion (STT) deformation at ambient temperature. The results show that stress-induced α″ martensite transformation has been activated which its volume fraction depends heavily on the deformation modes. There are groups of α″ structures with various morphology generated from the grain boundaries of separate β grains, which long strip-like and block-shaped structures after UT, zig-zag, needle-shaped, and block-shaped structures after ST, a combination of zig-zag, needle-shaped, block-shaped, and strip-shaped structures after STT were observed. Moreover, there is an apparent dynamic grain refinement and accumulation of geometrically necessary dislocations (GNDs) by UT, ST and STT deformation, and STT deformation mode is more conducive to the two effects. The average Vickers microhardness of as-received, UT, ST, and STT samples are ~295 HV, ~311 HV, ~324 HV, and ~351 HV. It is closely related to the dynamic grain refinement caused by the TRIP effect and GNDs accumulated. [Display omitted] • The stress-induced martensite transformation in Ti-10V-2Fe-3Al alloy by various deformation modes is investigated. • The remarkable grain refined and orientation relationship is displayed between the the martensite and parent phases. • The average value of Vickers microhardness improved and higher strain hardening effect are discussed. • The comprehensive properties improve predominantly under the interaction of normal stress and shear stress. [ABSTRACT FROM AUTHOR]