Detection of Lattice Deformation and Recovery in Epsilon Phase Silver-Tin Alloys

A line-broadening effect has been observed in x-ray diffraction patterns from powdered epsilon phase silver-tin base alloys which have been subjected to cold work. The line breadth is reduced when the alloy ingots have received a prior homogenization treatment at 400° C and is also reduced when cold-worked alloy particles are annealed at 100° C. It is shown that the reduction in line breadth which occurs at 100° C is the result of a recovery process which significantly reduces the amount of internal deformation present in the alloy particles. The presence of internal deformation in these cold-worked alloy particles has also been associated with a dimensional expansion which occurs when the silver-tin particles are reacted with mercury at room temperature. Spherical alloy powders produced by an atomization process were found to be relatively free of internal deformation but were not chemically homogeneous. Metallographic and x-ray diffraction data indicated, however, that the spherical alloy particles can be homogenized by a high temperature heat treatment.