A1-L12 Structures in the Al-Co-Ni-Ti Quaternary Phase System
The phase constituents of alloys from the (Ni,Co)85(Al,Ti)15 plane of the Ni-Co-Al-Ti quaternary system were investigated following prolonged exposure at 750°C. Microstructural investigations confirmed the existence of a continuous A1-L12 two-phase region in the Ni-Co-Al-Ti quaternary system between Ni-Ni3Al and Co-Co3Ti. The lattice misfits of alloys from this quaternary system were determined using neutron diffraction. With increasing contents of Ti the positive lattice misfit increases up to +0.79% in the Ti-containing alloys, which leads to an increasing tetragonal distortion of the matrix phase due to the increasing coherency stresses.
J. P. Minshull et al., "A1-L12 Structures in the Al-Co-Ni-Ti Quaternary Phase System", Advanced Materials Research, Vol. 278, pp. 399-404, 2011