MATERIALS
Utrafine-grained structure and thermal stability of the two-phase titanium alloy VT8M-1
In this work, the method of backscattered electron diffraction (EBSD) and transmission electron microscopy (TEM) was used for microstructural analysis of the improved VT8M-1 alloy (Ti-5.7 Al-3.8 Mo-1.2 Zr-1.3 Sn) subjected to equal-channel angular pressing (ECAP) and rotary forging (RF). It was found that the process of globularization induced during deformation processing is regulated by the conventional boundary-splitting mechanism. It was shown that an orientation relation is established between the spheroidized a – and bphases. This result is achieved due to the high activity of dislocation sliding at the boundary of the a-and b-phases. The thermal stability of the VT8M-1 alloy with an ultrafine-grained (UFG) structure is s -term (up to 500 hours) annealing the UFG structure is thermally stable. The mechanical properties and the effect of annealing on the microstructure are discussed. It is shown that particles of the Ti-Zr-Si system are isolated at the interphase boundaries.