METHOD FOR DETERMINING TEMPERATURE OF FULL POLYMORPHOUS TRANSFORMATION OF HEAT-RESISTANT TWO-PHASE TITANIUM ALLOYS OF (ALPHA+BETA)-MARTENSITIC CLASS

摘要

FIELD: metallurgy.;SUBSTANCE: method for determining temperature of full polymorphous transformation of heat-resistant two-phase titanium allows of (α+β)-martensitic class is proposed, which involves preliminary preparation of a specimen by means of multistage heat treatment of the latter, which is performed immediately in a differential thermal analysis (DTA) instrument in atmosphere of cleaned argon and its investigation using DTA method. Heating of the alloy specimen to single-phase β-area, supercooling below temperatures of active diffusional decay of β solid solution, short-term exposure and repeated heating to the single-phase area is performed. Fixation of dependence of a DTA signal on temperature and calculation of values of derivative of DTA signal on temperature is performed, and temperature of completion of full polymorphous transformation is determined as per maximum on the curve of the first derivative of DTA signal at repeated high-temperature heatinge.;EFFECT: improving determination accuracy of temperature of full polymorphous transformation in heat-resistant two-phase titanium alloys.;4 dwg