MICROSTRUCTURAL AND CRYSTALLOGRAPHIC CHARACTERIZATION OF MULTIPHASE AL62TI10V28 ALLOY

In a multiphase intermetallic alloy Al62Ti10V28, four principal phases have been identified to exist after chill-casting and post-solidifica tion heat treatments: beta-(Ti, V), a novel hexagonal H-2, bcc zeta-Al 8V5 and Ll(2)-based delta-Al-3(TI, V). Detailed electron diffraction a nalysis has defined the four phases and crystallographic relationships between these phases. The H-2 phase maintained an orientation relatio nship with the bcc zeta-Al8V5 phase, in the chill-cast condition, was such that: ((1) over bar 0 (1) over bar)(zeta)//(2 (2) over bar 0 (1) over bar)H-2 and [(1) over bar 11](zeta)//[11 (2) over bar 0](H2). The most closely-packed planes (110)(zeta) and (0001)(H2) were misoriente d by an angle of similar to 1.68 degrees. However, by annealing for 24 h at 1523 K, the close-packed planes become parallel to each other wi thin the limits of detectability and the Burgers orientation relations hip is established: (110)(zeta)//(0001)(H2) and [(1) over bar 11](zeta )//[11 (2) over bar 0](H2). In the alloy aged for 3 h at 1273 K, a two -phase delta/beta microstructure is obtained and the two phases show t he Pitsch orientation relationship: (101)(beta)//(001)(delta) and [(1) over bar 11](beta)//[(1) over bar 10](delta).