In this study, severe plastic deformation through high–pressure sliding (HPS) was applied for in situ high–energy X–ray diffraction analysis at SPring–8 in
JASRI (Japan Synchrotron Radiation Research Institute). Allotropic transformation of pure Ti was examined in terms of temperatures, pressures and imposed
strain using a miniaturized HPS facility. The true pressure applied on the sample was estimated from the peak shift. Peak broadening due to local variation of
pressure was reduced using white X–ray. The phase transformation from ÿ phase to ÿ phase occurred at a pressure of ÿ4.5 GPa. Straining by the HPS processing
was effective to promote the transformation to the ÿ phase and to maintain the ÿ phase even at ambient pressure. The reverse transformation from ÿ phase to ÿ
phase occurred at a temperature of ÿ110ÿ under ambient pressure, while under higher pressure as ÿ4 GPa, the ÿ phase remained stable even at ÿ170ÿ covered
in this study. It was suggested that the reverse transformation from the ÿ phase to the ÿ phase is controlled by thermal energy.