Solution‐Hardening and Deformation of Niobium‐Tungsten Alloys

The results of some experiments on the strain‐rate and temperature dependence of the flow stress of some dilute niobium‐tungsten alloys are reported. Alloys containing 0.25, 0.5, and 2.6 at% tungsten exhibit unusual twin peaks in the strain‐rate sensitivity as a function of temperature, and this leads to abnormally high values of the activation energy of deformation in the region of 150 °K. And yet the behaviour of a 5.3 at% W alloy appears to be indentical with that normally observed for b.c.c. metals. The results suggest that two deformation mechanisms are overlapping below 150 °K, and current theories of solute hardening and deformation of b.c.c. metals are examined to provide an explanation.