Solid-Solution-Hardening of Tantalum-Base Alloys

Solid-solution-hardening has been studied on single crystals of TaRe, TaW, TaMo, and TaNb with a fixed solute concentration of 3·5 at.-%. The critical resolved shear stress was measured over the temperature range 77–2000 K. It is found that ∆τ0, the difference in shear stress between the alloy and the pure tantalum, exhibits a plateau range between 1000 and 1500 K. The modulus misfit parameter ɛ G (K33), derived from the modulus that determines the stress field of a screw dislocation, is shown to be a very good parameter to describe solid-solution-hardening in tantalum.