TEM and XRD characterisation of commercially pure α-Ti made by powder metallurgy and casting

摘要

The hep-structured α-Ti is one of the two basic phases (α-Ti and βVTi) in Ti materials. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to analyse the α-Ti phase in both as-sintered and as-cast α-Ti materials. The structure factor of the (0001) plane of the α-Ti phase is 0. No diffraction should thus occur from the (0001) plane of the α-Ti phase when characterised by either x-ray diffraction or electron diffraction. However, electron diffraction of the as-sintered α-Ti materials recorded unambiguous diffraction from the (0001) plane as well as (0001) where 1 = 2n+ 1 (n is integer). A detailed analysis has clarified that this is a result of double diffraction arising from the two strong neighbouring (1010) and (1011) diffraction planes. The same phenomenon also occurred to the characterisation of as-cast α-Ti materials.