Abu-Bakr El-Bediwi

Structure, mechanical metallurgy and electrical transport properties of rapidly solidified Pb50Sn50-xBix alloys

Electrical transport properties, structure and mechanical properties of Pb50Sn50-xBix(0≤x≤50) alloys have been studied and analyzed. The addition of bismuth in the amounts of 30 wt % and 50 wt % results in the appearance of the crystalline metastable χ(Pb-Bi) phase. Y phase is also identified and it is found at 50 wt % bismuth. Electrical transport is sensitive to the alloys composition, decreasing as the bismuth content increases. The Vickers hardness number is sensitive to the structure of the quenched ribbons. The lowest value of Hv is 55 MPa for the Pb50Sn20Bi30 alloy, which is attributed to the formation of the metastable χ(Pb-Bi) after a rapid quench from the melt. Values of the equivalent Fermi temperature, TF Fermi velocity, VF and the Fermi wave vector, KF , are also computed.

Microstructure and physical properties of bismuth–lead–tin ternary eutectic alloy

Using different experimental techniques, microstructure, electrical resistivity, attenuation coefficient, and mechanical and thermal properties of the quenched Bi–Pb–Sn ternary eutectic alloy have been investigated. From the X-ray analysis, Bi3Pb7 and Bi–Sn meta-stable phases are detected, in addition to rhombohedral bismuth and Sn body-centered tetragonal phases. This study also compared the physical properties of the Bi–Sn–Pb ternary eutectic alloys with the base binary Bi–Sn and Bi–Pb eutectic alloys.

Structure, attenuation coefficients and physical properties of Bi–Pb–Sn fusible alloys

Shaped fields are widely used in radiotherapy to protect critical organs and to avoid unnecessary normal tissue irradiation. The most common system for photon-beam shaping consists in a low-melting point alloy. The structure and the attenuation coefficient of normally casted Bi–Pb–Sn fusible alloys have been investigated. These normal casting fusible alloys have an adequate half-value layer and attenuation coefficient, as compared to lead metal. Also some physical properties of quenched Bi–Pb–Sn alloys have been studied and analyzed. These Bi–Sn–Pb quenched alloys have better mechanical properties, such as a high elastic modulus and hardness and a lower melting point. These advantages make Bi–Pb–Sn fusible alloys very important for radiotherapy shielding blocks and industrial applications with a reduced quantity of lead.

Correlation study of structural, electrical and mechanical properties of quenched tin–zinc–cadmium solder alloys

It is important, for electronic application, to decrease the melting point of SnZn9 solder alloy because it is too high as compared with the most popular eutectic Pb–Sn solder alloy. Adding Cd causes structural changes such as phase transformations, dissolution of atoms and formation of Cd crystals in the quenched SnZn9 alloy, and its physical properties are affected by this change. For example, the melting point is decreased towards the melting point of the Pb–Sn eutectic alloy, or even much less. The structure, electrical and mechanical properties of quenched Sn91− x Zn9Cd x (xu2009=u20090 or xu2009≥u20095) alloys have been investigated. Adding Cd to a quenched SnZn9 alloy increases its electrical resistivity and decreases its elastic modulus and internal friction. The Sn71Zn9Cd20 alloy has the lowest melting point (162 °C) and electrical and internal frictions as compared with commercial Pb–Sn solder alloys.

Structure, mechanical and electrical transport properties of low-melting half bearing metal alloys rapidly solidified from melt

Structure, mechanical and electrical transport properties of Pb60Sn38 X 2(X=Sb, Bi, or Ag in weight percent as ternary additions) and Pb60+x Sn38−x Cu(x≤8 wt.%) rapidly solidified alloys have been investigated. The Pb88Sn10Cu2 alloy has good properties for automotive applications (FIAT Normalizzazione), such as minimum values of hardness and internal friction. It is found that the elastic modulus, hardness and conductivity improved by decreasing the lead content and increasing the tin content with constant copper content. It is also interesting to note that Ledbetters theoretical values of µ/E are in a good agreement with the experimental results.

Electrochemical corrosion behavior, Vickers microhardness, and microstructure of Co–Cr and Ni–Cr dental alloys

Electrochemical corrosion behaviors, Vickers microhardness, microstructure, and electrical properties of Magnum H50 (Co=64.5%, Cr=29%, Mo=6.5% ) and Nikkeli–Kromi–Polttosekoitus (Ni=65.2%, Cr=22.5%, Mo=9.5%, X=2.8% Nb, Si, Fe, and Mn) dental alloys have been investigated. The corrosion potential for the Co64.5Cr29Mo6.5 alloy in HCl was higher than that of the Ni65.2Cr22.5Mo9.5X2.8 alloy. The corrosion rate with 0.5 M HCl for the Ni65.2Cr22.5Mo9.5X2.8 alloy was measured as being high and the corrosion resistance as being small as compared with the values for the Co64.5Cr29Mo6.5 alloy. Vickers hardness of the Co64.5Cr29Mo6.5 alloy was higher than that of the Ni65.2Cr22.5Mo9.5X2.8 alloy. Also Vickers hardness values of the used alloys were decreased by increasing indentation load. The thermal conductivity and minimum shear stress values of the used alloys are calculated.

Hardness indentation measurements for large-grained polycrystals of the trivalent metal aluminium

Abstract Indentation microhardness measurements have been carried out on large-grained polycrystals of alluminium produced by strain-anneal crystal growth. Anisotropy in hardness has been observed and it is described as planar anisotropy. The resistivity is also determined for samples thermally and non-thermally treated. It has also been found that the resistivity measurements can be used to obtain the longitudinal strain (∊) and to estimate the mechanical modulus.

Room-Temperature Indentation Creep and the Mechanical Properties of Rapidly Solidified Sn-Sb-Pb-Cu Alloys

In this paper, we study the room-temperature indentation creep and the mechanical properties of Sn-Sb-Pb-Cu alloys. Rapid solidification from melt using the melt-spinning technique is applied to prepare all the alloys. The experimental results show that the magnitude of the creep displacement increases with the increase in both time and applied load, and the stress exponent increases with the increase in the copper content in the alloys which happens primarily due to the existence of the intermetallic compounds SbSn and Cu6Sn5. The calculated values of the stress exponent are in the range of 2.82 to 5.16, which are in good agreement with the values reported for the Sn-Sb-Pb-Cu alloys. We have also studied and analyzed the structure, elastic modulus, and internal friction of the Sn-Sb-Pb-Cu alloys.