Phases In Superalloys Research Articles

Influence of Co addition on the structure of the precipitated phase in superalloys

Influence of Co addition on the structure of the precipitated phase in superalloys

Tetrahedrally close-packed phases in superalloys: new phases and domain structures observed by high-resolution electron microscopy

The structure of tetrahedrally close-packed phases (known also as Frank-Kasper phases) in superalloys has recently been extensively studied at the atomic level by high-resolution electron microscopy (HREM) in the Laboratory of Atom Image of Solids, Academia Sinica. In addition to a magnitude of domain structures, no less than six new phases have been found. This is a resume of the study. First, a brief description of the crystal structures of these phases is given to illustrate the capability of HREM in revealing the building of complex structures from simple structural units. Secondly, the crystallographic features of the new phases and microdomain structures are discussed. Finally, the principle of juxtaposition of parallel oriented coordination polyhedra in these tetrahedrally close-packed phases is presented and this not only explains the existing structures of such phases but may also be important in the study of the quasi-crystalline state in rapidly quenched amorphous alloys.

Determination without standards of small amounts of metal compounds on microfilters by X‐ray fluorescence spectrometry

AbstractThe extracted minor phases in superalloys are analyzed by X‐ray fluorescence spectrometry without the use of standards. The calculation in the analysis is simplified by using a monochromatic X‐ray source and the fundamental parameter method. The extracts on the microfilter are approximated by thin film on the filter substrate, though the extracts were not homogeneous. This source permits a simple calculation using the thin film model to transform the measured X‐ray intensity to mass thickness and mass fraction, since the mass absorption coefficient for the primary beam is easily found in a commercially available table. A great advantage of this method is that the calculations are possible by using a small programmable calculator.

Chemical Analysis of Conjugate Phases in Superalloys

Chemical Analysis of Conjugate Phases in Superalloys