DECOMPOSITION OF THE BETA-METASTABLE PHASE OF THE TITANIUM-ALLOY BETA-CEZ DURING HEATING AND ANNEALING

This work carries out the study of the precipitation during continuous heating up to 830-degrees-C and ageing at this same temperature from beta meta + omega aniso or beta meta + alpha. The heating rates varied between 0.25 and 5-degrees-C/s. The transformations were followed by electric resistivity and hardness measurements. Different samples were quenched from different temperatures during the heating range and were then studied by X-ray and TEM. The beginning temperatures of precipitations of the omega and alpha phases were established, as the continuous heating transformation diagrams. Near 700-degrees-C, X-ray quantitative analysis and EAM studies revealed( for quenching and 4.5-degrees-C/s cooling rate) that the structure consisted of a maximum content of the alpha phase, surrounded by beta zones enriched in Fe, Cr. For temperatures greater than 700-degrees-C, the content of the alpha phase diminished and the beta phase composition was homogenized.