Electrophysical Properties of 2 Co–Ti–Al Alloy Produced by SHS Pressing

This article investigates the microstructural features, phase composition, and electrophysical properties of Co 2 TiAl intermetallic alloy produced by self-propagating high-temperature synthesis (SHS) in combination with pressing. For the first time, a practically single-phase alloy based on the Co 2 TiAl Heusler compound with the weight content of at least 82% was produced using SHS; the synthesis products also contain TiCo x intermetallic compounds of variable composition. The unit cell parameter of Co 2 TiAl was a = 5.8433 ± 0.0002 Å. Metallographic analysis of the microstructure after SHS pressing demonstrated structure densification and decrease in porosity in comparison with samples produced by regular SHS without application of load to the combusted sample. The average microhardness of the synthesized alloy was H μ = 5650 MPa, and the electrical resistance of the synthesized material at ambient temperature was 1.35 μΩ m. Variations of specific electrical resistance were studied in vacuum of 1.33 × 10 –3 Pa in the temperature range of 77–1300 K. At temperatures above 600 K, the electrical resistance as a function of temperature ρ( T ) in Co 2 TiAl alloy exhibits a decrease in slope; that is, for the given alloy, there exists the so-called effect of resistance saturation. The Curie point corresponding to transition from the magnetic to paramagnetic state was 133 K.