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 Tig = 650 ± 10°C, the maximum synthesis temperatures were in the range Tmax = 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 Tmax = 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.

Keywords

• precursors
• self-propagating high-temperature synthesis
• magnetron deposition
• dynamic diffractometry