Deformation of Nb-W single crystals: Athermal solid solution strengthening

The athermal component of the flow stress of single crystals of niobium and four substitutional solid solution strengthened Nb-W alloys (1, 3, 6, and 15 at. pct) has been measured. The magnitude of the athermal stress was obtained by the method utilizing the temperature dependence of the flow stress and by a stress relaxation method. The agreement between these two methods is good. Athermal strengthening is a linear function of concentration over most of the composition range. No current athermal hardening theory is completely consistent with the experimental results. Formerly with the Advanced Materials Research and Development Laboratory, Pratt and Whitney Aircraft, Middletown, Conn.,