Author/Authors :
L. Chauke، نويسنده , , H.R. and Minisini، نويسنده , , B. and Drautz، نويسنده , , R. and Nguyen-Manh، نويسنده , , D. and Ngoepe، نويسنده , , P.E. and Pettifor، نويسنده , , D.G.، نويسنده ,
Abstract :
The deleterious low-temperature tetragonal phases in prototypical Pt-based superalloys have variously been reported as taking the tI16-U3Si (DOc), tI16-Ir3Si (DOc′) and tP16-Pt3Ga structure-types in contrast to the high-temperature cubic cP4-Cu3Au (L12) phase. We have investigated the relative stability of these four structure-types at absolute zero by using density functional theory. We find that the ground state of stoichiometric Pt3Al is tP16-Pt3Ga and that the other three lattices are mechanically unstable at absolute zero. Experiments are needed to measure the internal displacement parameters of these three competing tetragonal phases.
Keywords :
B. Alloy design , E. Phase stability , Predictions , A. Intermetallics , miscellanenous
