In situ X-ray diffraction study of the phase transformation in the non-stoichiometric intermetallic compound Ti3Sn

•A new orthorhombic phase of the intermetallic compound Ti3Sn was found.•A reversible orthorhombic-to-hexagonal transition into Ti3Sn was observed using XRD.•The unit cell and space group of orthorhombic phase are defined.•Crystallographic relations between orthorhombic and hexagonal phases are analyzed.

Phase transformations of Ti75.5Sn24.5 were investigated using in situ X-ray diffraction during heating. The as cast Ti75.5Sn24.5 was found to consist mainly of an orthorhombic Cmcm phase at room temperature; upon heating to 473 K the material undergoes a reversible group-subgroup transition to hexagonal P63/mmc (D019) phase. Crystal structure and lattice parameters of the orthorhombic phase are suggested based on X-ray and electron diffraction results. The crystallographic relation between parent and product phase is also discussed.