In situ phase formation during high-temperature synthesis in clad mechanocomposites based on the Ti-Al system.

Abstract

An in situ synchrotron experimental study of phase formation dynamics in clad mechanocomposites of Ti-Al systems during high-temperature synthesis was performed. Cladding of the obtained mechanocomposites was carried out with an SiO₂ target, with a deposition time of 40 min. The high-temperature synthesis was performed using the thermal explosion method based on a microwave induction heater in the in situ mode on an experimental setup adapted to synchrotron radiation time-resolved diffractometry. The influence of the cladding on the macrokinetic parameters of synthesis in situ was investigated experimentally. It was found that for an ignition temperature T_ig = 650 ± 10°C, the maximum synthesis temperatures were in the range T_max = 1380-1465°C. The characteristic heating speed was 525 K min^-1. The sequence and temperature-time interval of phase formation are determined. The formation of the TiAl, TiAl₃ and Ti₃Al compounds begins at T = 661°C. At T_max = 1465.6°C, the synthesis product is multiphase, the structures of the formed TiAl₃ (content about 70%) and TiAl (content about 25%) have a nonequilibrium state. At the stage of system annealing with T = 1384.9°C, the reaction of the components occurs with the formation of almost monophase TiAl (content of more than 90%); Ti occupies the rest.