[en] Investigations have shown that lanthanum at ambient temperature withstands strain of 16% without failure. In the temperature range of 300-600 deg C lanthanum can be rolled without failure at a single pass reduction of 50-80%. At 700 deg C a decrease in the allowable strain is observed down to 66-70% being caused by intensive lanthanum oxidation. The relationship between mean specific pressure and strain is presented. Most intensively, the specific pressures as a function of strain are increased at ambient temperature. This is accounted for by the presence of lanthanum α-phase. A considerable decrease in specific pressures is observed at temperatures 100 and 400 deg C as compared with 20 and 300 deg C respectively. This is explained by an allotropic transformation taking place in lanthanum at elevated temperature. Up to 260 deg C lanthanum structure consists of α+β phases and at higher temperatures, of β-phase having the f.c.c. crystal lattice. Metals with this type of lattice have a lower resistance to deformation than those with the hexagonal one and possess high ductility levels

[en] Microstructure and phase composition of yttrium of various purity were studied by metallography and X-ray phase analysis. The investigation technique and characteristics of impurity phases are presented: YN, I₂O₃, YOF. The conclusion is made that the metallography method makes it possible to detect and identify impurity phases in commercial yttrium