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Sb Alloys (sb + alloy)

Distribution by Scientific Domains

Physics and Astronomy	80%

Selected Abstracts

Dendritic solidification of binary alloys with free and forced convection

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 3 2005
P. Zhao
Abstract Dendritic solidification with forced convection and free convection driven by contraction and thermo- solutal buoyancy is simulated in two-dimensional space using a sharp-interface model. Both pure substances and alloys are considered. The model is formulated using the finite element method and works directly with primitive variables. The coupled energy- and solutal concentration-equations, along with the Navier,Stokes equations for incompressible flow, are solved using different meshes. Temperature is solved in a fixed mesh that covers the whole domain (solid + liquid) where the solid,liquid interface is explicitly tracked using marker points. The concentration and momentum equations are solved in the liquid region using an adaptive mesh of triangular elements that conforms to the interface. The velocity boundary conditions are applied directly on the interface. The model is validated using a series of problems that have analytical, experimental and numerical results. Four simulations are presented: (1) crystal growth of succinonitrile with thermal convection under two small undercoolings; (2) dendritic growth into an undercooled pure melt with a uniform forced flow; (3) equiaxial dendritic growth of a pure substance and an alloy with contraction-induced convection; and (4) directional solidification of Pb,0.2 wt% Sb alloy with convection driven by the combined action of contraction, thermal and solutal buoyancy. Some of the simulation results are compared to those reported using other methods including the phase-field method; others are new. In each case, the effects of convection on dendritic solidification are analysed. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Study of the mechanical and thermal properties of Sn,5 wt% Sb solder alloy at two annealing temperatures

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003
M. M. EL-Bahay
Abstract Sn,5 wt% Sb alloy is one of the materials considered for replacing lead-containing alloys for soldering in electronic packaging. Differential thermal analysis (DTA) and specific heat of the sample were studied. Wetting contact angle measurements of the alloy on different substrates were carried out at high temperature. Microhardness tests as a function of temperature were performed to calculate the effective activation energy of the solder alloy Sn,Sb and compared with the pure elements Sn and Sb. Isothermal creep curves for alloy samples were obtained under different constant applied stresses at different working temperatures ranging from 463 K to 503 K, followed by annealing the samples at two different temperatures before and above the threshold value (Tm/2). The transient creep parameters and the values of the stress exponent n were calculated for the two annealing temperatures. Microstructure examinations of the as-cast alloy at room temperature and after the two annealing treatments with the effect of the cold work deformation and creep test on the structure change and properties of Sn,Sb alloys were reported. The stress rupture test was also measured. [source]

Positron preferential annihilation in Bi,Sb alloys

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2009
Jerzy Dryzek
Abstract We report the measurements of the positron annihilation characteristics, i.e., positron lifetime and coincidence Doppler broadening spectra performed on five Bi,Sb alloys having a Bi content between 12.5 and 81,at.%. The strong effect of the preferential annihilation of positrons with the electrons of the Bi atoms has been revealed in these alloys. [source]