Аңдатпа
The article is devoted to the development of a methodology for microstructural and thermal verification of the quality of an industrial Ti-10V-2Fe-3Al triple vacuum arc remelted ingot produced by UK TMP JSC. It was established that all zones of the ingot demonstrate a two-stage thermal evolution characteristic of the β-metastable Ti-10V-2Fe-3Al alloy: decomposition of the metastable β phase (≈520–570 °C) and an endothermic α→β phase transformation (≈950–1120 °C). It was found that the enthalpy of the exothermic decomposition of the β matrix increases by approximately 60–80% in the lower zone of the ingot. The width of the phase transition (ΔT) correlates with an increase in microsegregation. It was also determined that the enthalpy of the endothermic α→β transformation decreases from the bottom part of the ingot toward the steady-state crystallization zone (Middle-1), which correlates with a reduction in the microsegregation parameters obtained from SEM–EDS profiles (ΔC_max, σC, Lcorr). Thus, thermal analysis confirms the absence of a pronounced vertical gradient of structural stability and can be used as a validating criterion for the integral electrode quality index. For the first time, a quantitative correlation between SEM–EDS profiles and DSC–DTG characteristics has been proposed. Thermal analysis is suggested as an independent validator of microsegregation. An approach to the quantitative evaluation of microsegregation based on SEM–EDS profiles using the parameters ΔC_max, σC, Lcorr, and ΔCO(local) has been developed. Additionally, the use of an integral chemical index Ichem, and a critical threshold Icritchem is proposed for electrode quality control using thermal analysis results.