MORPHOLOGY AND HIGH RESOLUTION IMAGE OF EUTECTOID TRANSFORMATION PRODUCTS OF Ti-H ALLOYS

The morphology and the fine structure of the hydrides in Ti-H alloys, containing 0.2-1.53 wt-% hydrogen, were investigated by TEM. It was found that the eutectoid transformation products from β-Ti(H) were consisted of δ hydrides and α-Ti,forming a micro-polycrystalline aggregate, while γ hydride was precipitated from α-Ti(H) directly. The atomic structure of these microcrystals were carefully delineated by HRTEM, showing that there may be ten variants of α-Ti around δ hydrides, which can keep two definite crystallographic relationships with α-Ti. The shear mechanism of the eutectoid transformation is discussed.