Solid solution hardening of molybdenum–hafnium alloys: Experiments and Modeling

In the present work the solid solution hardening (SSH) of the molybdenum–hafnium system (0.30–2.9 at% Hf) was investigated over the temperature range 448–1073 K. Particular attention was given on the manufacturing of the alloys in order to determine the critical resolved shear stress without the contribution of additional strengthening mechanisms, like particle, Hall–Petch or work hardening. It was revealed that hafnium is a strong solid solution hardener in molybdenum. In the course of this paper it was shown that the SSH of the Mo–Hf system was predicted with the model of Labusch only by using the atomic misfit parameter. Therefore the lattice parameters were calculated by an approach which was developed by Lubarda [V. Lubarda, Mechanics of Materials 35 (2003) 53–68]. For the prediction of the critical resolved shear stress as a function of the temperature the “trough model” was used. Finally the predictions of the models were compared to the experimental data.