SOLUTION HARDENING OF LEAD SINGLE CRYSTALS AT LIQUID AIR TEMPERATURE

Single crystals of lead with either thallium, indium, bismuth, cadmium, mercury or antimony were tested in tension in liquid air. The critical resolved shear stress τ0 increases linearly with increasing solute content c in a limited concentration range. The increase Δτ0/ΔC is lowest for lead-thallium and highest for lead-antimony. When log Δτ0/ΔC is plotted against log (sf + elf) where sf*[(d1)Pb - (d1)sol/(d1)Pb]10Pb, d1 being the closest distance of approach, and elf = ΣEn, ΣEn being the sum of the electronegativities of solvent and solute, a straight line of slope 2 results. A similar result is obtained with data from the literature for single crystals of copper alloys and of magnesium alloys. However in these cases a different size factor has to be used. © 1969 Chapman and Hall.