Synthesis of ternary L10 compounds of Ti–Al–Zr system and their mechanical properties

Abstract

Abstract A number of ternary Ti–Al–Zr alloys with different compositions around the binary γ-TiAl (L1 0 structure) were prepared and annealed at 1273 K for 10 h followed by quenching. Almost single γ-phase is produced in a rather wide composition region of Al 50 (Ti 50− x − y Al x Zr y ) with 0 ≤ x ≤ 15 and 0 ≤ y ≤ 15. Both lattice parameters, a and c increase with increasing Zr concentration due to larger atomic radius of Zr than those of Al and Ti. The c / a ratio of Al 50 Ti 50− x Zr x decreases towards unity as x increases. The Vickers hardness value increases rapidly with increasing Zr substitution. Compression tests at high temperatures for Al 50 Ti 50− x Zr x and Al 55 Ti 45− x Zr x with x = 5, 10 or 15 showed that except for Al 50 Ti 45 Zr 5 , specimens underwent brittle fracture below 1000 K; only the Al 50 Ti 45 Zr 5 specimens exhibited a considerable plastic strain at all the test temperatures, and the temperature dependence of the yield stress showed a peak at 973 K with the peak yield stress as high as 1000 MPa, indicating a possible application of this ternary alloy.