Phase instability in dilute interstitial solid solutions of nitrogen in tantalum

An ordered structure is found in interstitial solid solutions as dilute as 0.1 at. nitrogen in tantalum. On the basis of the symmetry of the ordered structure, tetrahedral rather than the usual octahedral sites are considered appropriate for the nitrogen atoms. The effect of the ordered structure on the properties of the solid solution are discussed. © 1962 The American Institute of Physics.