Abstrakt
Phase transitions in a single crystal of a metastable beta -titanium alloy (Ti-15Mo) were investigated in situ during heating by synchrotron X-ray diffraction. The results were compared with previous measurements of electrical resistance.
Single-crystalline samples allowed different crystallographic families of omega -Ti and alpha -Ti phases to be distinguished. The observed evolution of the intensity of the reflections of the omega phase during heating is consistent with the evolution of electrical resistance, which proves that the resistance is affected by the presence of omega -phase particles.
Between approximately 673 and 833K, both the resistance and the intensity of omega peaks sharply decrease. At 833K, omega reflections disappear, indicating a complete dissolution of the omega phase due to achieving the solvus temperature of the omega phase in the Ti-15Mo alloy.
The synchrotron X-ray diffraction experiment proved that the disappearance of the omega phase during heating of Ti-15Mo with a heating rate of 5Kmin(-1) occurs by its dissolution back to the beta phase and not by omega -> alpha transformation.