Precipitation in a Ni–Al–Mo Directionally Solidified Eutectic Composite
The most recently developed high temperature materials are known as in-situ composites or directionally solidified eutectics. Since the composites are formed during solidification, they have excellent morphological stabilities up to near their melting temperatures. The Ni-Al-Mo system has received the greatest attention for recent several years(1)~(3) since the alloy is expected to form a structure consisting of ductile α-Mo fibers aligned in aductile γ+γ' matrix†. However variations in microstructures and the resultant strength by thermal treatments have not been investigated in earlier papers(1)~(3). In a separate paper(4) the present authors have reported the detailed microstructural analysis of as-grown composite and the microstructural and strength variations of the composite due to quenching from high annealing temperatures. The present paper describes the microstructural changes occurring during ageing of a Ni-12.7at%Al-21.6at%Mo alloy composite after quenching from 1533K studied by transmission electron microscopy
Effect of heat treatment on the fracture behaviour of directionally solidifiedγ/γ′-α alloy
Interet des composites in situ Ni−Mo−Al en raison de leur application possible dans les turbines a gaz. Constitution comprenant des fibres a section carree de Mo enrobees dans une matrice γ' (intermetalllique a base de Ni 3 Al), ou γ (solution solide de Ni)/γ'. Effet de differents traitements thermiques sur le travail de rupture et la microstructure d'un tel alliage de composition ponderale Ni-33 Mo-5,7 Al
Short-range order in a gold–40.0 atomic per cent palladium alloy
The local atomic arrangements in an Au-40 at.% Pd alloy were investigated by measuring the X-ray diffuse scattering from a single crystal. A computer simulation of the short-range structure was used in the interpretation of the diffuse scattering results. The interpretation indicated a tendency toward the formation of a tetragonal AB long period superlattice which has not previously been observed to occur. The static displacements of the atoms from their average positions were shown to be very small in this alloy.