United Technologies Corporation

Frank D Lemkey

Bernard H Kear

David D Pearson

A high strength nickel base superalloy having a novel microstructure is described. The article consists of a gamma matrix containing a oriented gamma prime second phase having a plate or rod form. This noncuboidal gamma prime phase is produced by aging solution treated material under an applied stress. When this process is applied to a certain class of superalloys which are rich in refractory elements, the resultant structure provides exceptional resistance to creep at elevated temperatures.

Superalloy properties through stress modified gamma prime morphology

An alloy composition coasting scheme and specific heat treatment process are described for the production of directionally solidified single crystal articles which have exceptional properties. The alloy is based on the Ni-Al-Mo system, preferably with additions of Ta. The process for producing the article inclused directional solidification at a high rate to produce a fine dendritic microstructure. A combined homogenizing and solution treatment is performed to provide a unique chemically homogeneous single phase microstructure. This homogeneous article is rapidly quenched and then aged at an intermediate temperature to develop a controlled uniform distribution of fine gamma prime phase particles.

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Glastonbury, CT, United States of America

Frank D Lemkey