FAULTING IN COMPACTED AG-9AT/OSN ALLOY POWDERS.
YALE UNIV NEW HAVEN CT DEPT OF ENGINEERING AND APPLIED SCIENCE
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An analysis was made of x-ray powder pattern peaks from silver-9 atomic per cent tin alloy powders compacted into briquets 1 in. diameter with pressures up to 320 kpsi. Lattice parameter measurements indicate the presence of deformation stacking faults probability alpha about 0.21 at the highest pressure and small residual stresses of the order of 5 to -6 kgsq mm 7000 to -8500 psi. Fourier analyses of the line profiles were carried out on the 111-222 and 200-400 pairs of reflections. Pressures of 40 kpsi produce an appreciable amount of plastic deformation which is responsible for the observed effective particles sizes D sub e111170A and sub e100100A. Increasing the pressure to 320 kpsi, the particle sizes decrease to D sub e111110A and D sub e10050A. The anisotropy of the particle sizes is a consequence of the presence of microtwins and deformation faults on the 111 planes. The twin fault probability beta was separately estimated from the asymmetric 111 and 200 line profiles, and was found to increase from beta 0.015 for 40 kpsi pressure to beta 0.030 for 320 kpsi pressure.
- Metallurgy and Metallography