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This study discussed the influence of chemical composition on the conductivity and on some mechanical properties of Mg-doped Cu-Si alloy. The structural changes accompanying variations of the alloy chemical composition was investigated using Carl ZEISS Scanning Electron Microscope (SEM) (EVO/NA10) and Energy Dispersive Spectroscopy (EDS). The study also discussed the implication of structural changes on the electromechanical behavior. The results obtained were analyzed statistically using one-factor response surface method (RSM-Design Expert software) to evaluate the level of significance of magnesium addition on Cu-3Si-Mg ternary alloy properties. The SEM results revealed fine grains in the Mg-doped Cu-3Si alloy. The study recorded improvement of properties: average ductility of 25.1%, UTS of 285 MPa; hardness of 318 BHN and average electrical conductivity of 53.9% IACS. The statistical analysis indicated that magnesium significantly improved all the tested properties haven recorded P -values < 0.05. The result of optimization revealed Cu-3Si-0.837 Mg as the optimal composition. [ABSTRACT FROM AUTHOR]

Addition of a small amount of Ca improves the ductility of Mg alloys. However, the mechanism underlying this effect is not well understood. In this work, tensile testing of an extruded Mg−0.47 wt% Ca alloy was conducted inside a scanning electron microscope. Electron backscattered diffraction-based slip trace analysis was performed to study in-grain slip activities at 1%, 2%, 4%, 8%, and 16% tensile strain. While the majority of the grains were deformed by { 0001 } < 11 2 _ 0 > basal slip, slip lines from { 1 1 _ 00 } prismatic planes and { 1 1 _ 01 } pyramidal I planes were also frequently observed, and their fractions increased with strain. Ex situ transmission electron microscopy indicated that the pyramidal I slip lines were associated with dislocations instead of dislocations. From Schmid factor analysis, the critical resolved shear stresses of prismatic slip and pyramidal slip are approximately twice that of basal slip in this Mg–Ca alloy. The enhanced activity of non-basal slip improved the material's ductility. Our first-principles calculations found that solute Ca atoms would reduce the unstable stacking fault energy for all slip modes. • Mechanism of ductility enhancement in Mg by Ca alloying was investigated. • Slip trace analysis showed different slip system activities at different strains. • Ca addition was found to enhance the activity of non-basal slip. • Influence of Ca on the GSFE curves of different slip systems was assessed. [ABSTRACT FROM AUTHOR]

• The addition of boron can effectively refine the grain size and improve the tensile strength of the alloy at room temperature. • With the increase of boron content, the complex permittivity and permeability of the material are significantly improved, and the microwave absorption performance at low frequency is improved. • When the boron content is 0.06 at%, the minimum reflection loss peak reaches −10.7 dB at 1.9 GHz. Flaky FeSiAlB alloy powders were prepared by melting, quenching and milling. The effects of boron on the microstructure of FeSiAl alloy powders, the element distribution on the grain boundary of parent alloy, and the room temperature tensile properties of as-quenched sheet were studied by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS) and tensile testing machine, respectively. With the addition of boron, the grain size of the master alloy was refined, and the tensile strength of the quenched sheet at room temperature was significantly improved. And obvious boron-rich regions were observed at grain boundaries. Soft magnetic properties were measured by vibrating sample magnetometer (VSM). Based on the electromagnetic parameters measured by vector network analyzer (VNA), the microwave absorption properties of flaky powder were calculated. The particles with high flake have high permittivity and permeability. Reflection loss (RL) shows that when B content amount was 0.06 at%, the absorption performance of the original FeSiAl absorbing material is improved in L and S bands, and the absorption peak moves from high frequency to low frequency. Excessive B element will lead to impedance mismatch, and the absorption performance in L and S bands will gradually decrease. For FeSiAlB flaky powder with 0.06 at % B content, the RL is −10.7 dB at 1.9 GHz and the matching thickness is 3 mm. [ABSTRACT FROM AUTHOR]

Tensile ductility of the Ti-based composites, which consist of a β-Ti phase surrounded by ultrafine structured intermetallics, is tunable through the control of intermetallics. The two Ti-based alloys studied exhibit similar compressive yield strength (about 1000MPa) and strain (about 35%-40%) but show a distinct difference in their tensile plasticity. The alloy Ti71.8Nb14.1Ni7.4Al6.7 fractures at the yield stress while the alloy Ti71.8Nb14.1Co7.4Al6.7 exhibits about 4.5% of tensile plastic deformation. To clarify the effect of microstructure on the deformation behavior of these alloys, tensile tests were carried out in the scanning electron microscope. It is shown that the distribution as well as the type of intermetallics affects the tensile ductility of the alloys. [ABSTRACT FROM AUTHOR]

In this technical paper, the microstructure, hardness, tensile deformation and final fracture behaviour of an emerging titanium alloy for performance-critical applications are presented and discussed. Both longitudinal and transverse test specimens were prepared from the as-provided sheet stock of the alloy and deformed in uniaxial tension. The yield strength and tensile strength of the alloy sheet in the transverse orientation was higher than the longitudinal orientation. The ductility of the test specimens, quantified in terms of reduction-in-cross-sectional area, was higher for the transverse specimen when compared to the longitudinal counterpart. The elongation-to-failure of the test specimens was identical in the two orientations of the sheet stock. The tensile fracture behaviour of the alloy was quantified by careful examination of the fracture surfaces in a scanning electron microscope. The intrinsic fracture features on the tensile fracture surface were discussed taking into consideration the nature of loading and contribution from intrinsic micro-structural features. [ABSTRACT FROM AUTHOR]

Abstract: Effects of crystalline phase particles formed in a strip-cast Zr-base bulk amorphous alloy on strength, ductility, and fracture toughness were investigated by directly observing microfracture processes using an in situ loading stage installed inside a scanning electron microscope chamber. The compressive and fracture toughness test results indicated that strength, ductility, and fracture toughness of the strip-cast amorphous alloy were higher than those of the as-cast monolithic amorphous alloy, although the strip-cast alloy contained a considerable amount (4.5vol.%) of hard, brittle crystalline particles. According to the in situ microfracture observation, crystalline particles were easily cracked under low stress levels, acted as blocking sites of shear band or crack propagation, and provided initiation sites of multiple shear bands. Thus, the improvement of mechanical properties in the strip-cast alloy could be explained by mechanisms of (1) blocking of crack propagation, (2) formation of multiple shear bands, and (3) crack deflection by crystalline particles. [Copyright &y& Elsevier]