The critical resolved shear stress of tantalum base alloys was measured from -196C to 300C and of niobium base alloys from -196C to 1800C. The behavior at low temperatures is complex. Certain features can, however, be recognized as significant: Both indirect and direct interactions contribute to the critical resolved shear stress. At high temperatures solid solution hardening is associated with an elastic interaction between solute atoms and dislocations. The modulus misfit parameter is more important than the size misfit parameter in describing the hardening.

This report presents the results of a state-of-the-art survey covering tantalum and seven of its alloys. All data are given in tabular and graphical form covering some of the more important physical, mechanical, and metallurgical properties for each material. References are given at the conclusion of each material section.