The formation of topologically closed packed (TCP) phase was studied for a series of nickel base superalloys containing rhenium. The alloys were found to form three types of TCP phases: rhombohedral mu, tetragonal sigma and a relatively unknown orthorhomic phase, P. The crystal structures of these phases are closely related. They often coexist in the alloy, even within the same precipitate. The segmented appearance of the precipitates is due to a basket weave morphology, consisting of ribbons of precipitates, overlapping at 90 degree angles. Computer programs such as PHACOMP which are used to predict alloy stability do not necessarily provide good correlation with TCP formation in Re containing alloys. The paper describes in detail the nature and formation of TCP phases in one specific alloy composition.
Formation of topologically closed packed phases in nickel base single crystal superalloys
Bildung von topologisch dichtest gepackten Phasen in Nickelbasis-Einkristall-Superlegierungen
1988
10 Seiten, 7 Bilder, 4 Tabellen, 5 Quellen
Conference paper
English
ENERGIEDISPERSIVE ROENTGENSPEKTROMETRIE , ORTHORHOMBISCHE STRUKTUR , TRANSMISSIONSELEKTRONENMIKROSKOPIE , MIKROANALYSE , AUSSCHEIDUNGSPRODUKT , MIKROGEFUEGE , SUPERLEGIERUNG , KRISTALLPHASE , EINKRISTALL , SIGMA-PHASE , MY-PHASE , BEUGUNGSBILD , PHASENUMWANDLUNG , STABILITAET , BERECHNUNG , ZTU-SCHAUBILD , ORIENTIERUNGSBEZIEHUNG , HABITUSEBENE , WACHSTUMSMECHANISMUS , TURBINE , RHENIUM
Wrought Nickel-Base Superalloys Final Report
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