DECOMPOSITION OF BETA-METASTABLE PHASE IN BETA-CEZ ALLOY DURING CONTINUOUS HEATING

The decomposition of the metastable beta phase in beta Cez alloy has b een studied during continuous heating up to 830 degrees C. The heating rate varied between 0.25 and 5 degrees C/s. Electric resistivity meas urements, and hardness measurements revealed different phase transform ations as temperature increased. Different samples were quenched from different temperatures during the heating range and were then studied by X-ray and TEM, allowing to correlate the changes in resistivity mea surements to the beginning of the precipitations of the omega and a ph ases and to establish the continuous heating transformation diagram. A change in the resistivity variations, not dependent on the heating ra te was observed near 700 degrees C. X-ray quantitative analysis and EA M studies revealed that the structure consisted of a maximal content o f alpha phase, surrounded by beta rich zones in the matrix. For temper atures greater than 700 degrees C, the content of alpha phase diminish ed and the beta phase was homogenized.