Kinetics of [gamma][prime] precipitation and its influence on fatigue crack growth behavior of a new single-crystal nickel-based superalloy (CMSX-4G) at room temperature

Journal Article · Mon Feb 01 00:00:00 EST 1993 · Journal of Materials Engineering and Performance; (United States)

DOI:https://doi.org/10.1007/BF02649675· OSTI ID:6491170

Sengupta, A; Putatunda, S K ^[1]

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1. Wayne State Univ., Detroit, MI (United States)

An investigation was carried out to determine the growth kinetics of [gamma][prime] precipitates in a newly developed single-crystal nickel-base superalloy containing rhenium (CMSX-4G). The investigation also examined the influence of [gamma][prime] precipitates (size and distribution) on fatigue crack growth behavior of the material in a room-temperature ambient atmosphere. The influence of load ratio on fatigue threshold of the material and crack growth mechanisms in fatigue was also studied. Compact tension specimens were prepared from a single-crystal nickel-base superalloy, CMSX-4G, with the <001> crystallographic direction. These specimens were given two different heat treatments to produce two different [gamma][prime] size precipitates. Fatigue crack growth behavior of these materials was studied at three different load ratios (R = 0.10, 0.50, and 0.90) in room-temperature ambient atmosphere. The results of the present investigation demonstrate that rhenium additions in CMSX-4G substantially lowers the [gamma][prime] coarsening kinetics of this alloy. The smaller [gamma][prime] precipitate size was found to be beneficial for fatigue resistance and has resulted in a higher fatigue threshold and lower fatigue crack growth rate in the threshold region. The fatigue threshold was found to decrease with an increase in load ratio. The crack growth mechanism in the threshold region was found to occur by a combination of microvoid coalescence and striations.

• OSTI ID: 6491170
• Journal Information: Journal of Materials Engineering and Performance; (United States), Vol. 2:1; ISSN 1059-9495
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
HEAT RESISTING ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NICKEL BASE ALLOYS
AMBIENT TEMPERATURE
CRACK PROPAGATION
FATIGUE
MONOCRYSTALS
PERFORMANCE TESTING
PRECIPITATION
RHENIUM ALLOYS
USES
ALLOYS
CRYSTAL STRUCTURE
CRYSTALS
HEAT RESISTANT MATERIALS
MATERIALS
NICKEL ALLOYS
SEPARATION PROCESSES
TESTING
360103* - Metals &amp; Alloys- Mechanical Properties
360102 - Metals &amp; Alloys- Structure &amp; Phase Studies