Precipitation in LiF-MgF2 Solid Solutions |
| |
| Authors: | VLADIMIR D KRSTIC PATRICK S NICHOLSON GARY R PURDY |
| |
| Affiliation: | Department of Metallurgy and Materials Science, McMaster University, Hamilton, Ontario, Canada |
| |
| Abstract: | Precipitation was studied for LiF single crystals containing up to 4 wt% MgF2. Replica electron microscopy observations, combined with hardness and lattice parameter measurements, showed that, irrespective of the level of MgF2, precipitation consistently occurs during quenching. Rapidly cooled crystals with lower MgF2 concentrations (<1 wt%) develop large cruciform particles of a metastable phase with approximate composition MgF2-6LiF. Lower cooling rates or higher MgF2 contents caused transformation of these metastable particles to rod-shaped stable MgF2 phase. This occurs via nucleation on the metastable crosses. The large misfit between the LiF matrix and the MgF2 phase causes development of an incoherent interface and an associated disturbance of a propagating crack was observed near each MgF2 particle. |
| |
| Keywords: | |
|
|
