ABSTRACTAl5Ti3 single-phase single crystals with the stoichiometric composition of Ti-62.5at.%Al were obtained by the floating zone method and subsequent heat treatment at 750°C for 48h. The crystals contain no L10 phase, but compose of anti-phase domains (APD) surrounded by the anti-phase boundary (APB) on the basis of the Al5Ti3 long-period superstructure.Orientation dependence of plastic deformation behavior and operative slip system were examined in compression in a wide temperature range between RT and 750°C using the single-phase single crystals in comparison with Al-rich TiAl single crystals with the L10 matrix and Al5Ti3 precipitates. In the wide crystal orientation area, {111)<110] ordinary slip appeared independent of the tested temperature, while {111)<101] superlattice slip was operative only at around [001] and [110] axes. This is because the critical resolved shear stress (CRSS) for the ordinary slip is lower than that for the superlattice slip and that for the ordinary slip in other Al-rich TiAl crystals containing L10. This implies that existence of the L10 matrix with the Al5Ti3 phase must be closely related to strengthening for the ordinary slip, similarity in Ni-base super-alloys consisting of the Ni-based matrix and L12 precipitates. The CRSS for both slips gradually decreased or was kept constant with temperature, showing no remarkable anomalous strengthening.In this paper, deformation mechanism in Al5Ti3 single-phase single crystals will be discussed focusing on condition of the Al5Ti3 superstructure.
Orientation Dependence of Plastic Deformation Behavior and Fracture Energy Absorption Mechanism around Vickers Indentation of Textured Ti3SiC2 Sintered Body
