The alloy was deformed in compression at high temperatures and it was found that it was brittle below 850C, but exhibited plasticity above 900C. The thermodynamic parameters for plastic deformation were determined, and the dislocation structure was monitored using transmission electron microscopy. The activation volume first fell rapidly with stress to about 100MPa, and then decreased slowly to reach a value of about 0.3nm3 at stresses above 150MPa. Most of the dislocations which were introduced by plastic deformation had <001> Burgers vectors. The magnitudes of these Burgers vectors were 0.398 or 0.502nm. The measured activation volumes at high stresses were therefore a small multiple of b3. It was concluded that plastic deformation of the alloy at high temperatures was controlled by a Peierls mechanism. It was assumed that the dislocations were not dissociated.

The Mechanical Properties and Dislocation Structure of a LaNi5 Alloy. K.Okada, A.Nohara, H.Saka: Philosophical Magazine Letters, 1999, 79[9], 699-707