Mechanisms of High Temperature/Low Stress Creep of Ni-Based Superalloy Single Crystals

Technical Report · Thu Mar 05 04:00:00 EST 2009

DOI:https://doi.org/10.2172/948728· OSTI ID:948728

Mills, Michael J ^[1]

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1. Department of Materials Science and Engineering

Cast nickel-based superalloys are used for blades in land-based, energy conversion and powerplant applications, as well as in aircraft gas turbines operating at temperatures up to 1100 C, where creep is one of the life-limiting factors. Creep of superalloy single crystals has been extensively studied over the last several decades. Surprisingly, only recently has work focused specifically on the dislocation mechanisms that govern high temperature and low stress creep. Nevertheless, the perpetual goal of better engine efficiency demands that the creep mechanisms operative in this regime be fully understood in order to develop alloys and microstructures with improved high temperature capability. At present, the micro-mechanisms controlling creep before and after rafting (the microstructure evolution typical of high temperature creep) has occurred have yet to be identified and modeled, particularly for [001] oriented single crystals. This crystal orientation is most interesting technologically since it exhibits the highest creep strength. The major goal of the program entitled ''Mechanisms of High Temperature/Low Stress Creep of Ni-Based Superalloy Single Crystals'' (DOE Grant DE-FG02-04ER46137) has been to elucidate these creep mechanisms in cast nickel-based superalloys. We have utilized a combination of detailed microstructure and dislocation substructure analysis combined with the development of a novel phase-field model for microstructure evolution.

• Research Organization: The Ohio State University, Columbus, Ohio
• Sponsoring Organization: USDOE
• DOE Contract Number: FG02-04ER46137
• OSTI ID: 948728
• Report Number(s): DOE/FG/ER46137
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AIRCRAFT
ALLOYS
CREEP
DISLOCATIONS
EFFICIENCY
ENERGY CONVERSION
ENGINES
GAS TURBINES
HEAT RESISTING ALLOYS
MICROSTRUCTURE
MONOCRYSTALS
ORIENTATION