Accession Number : ADA189526

Title :   The Effect of Microstructure on the Fatigue Crack Growth Resistance of Nickel Base Superalloys.

Descriptive Note : Final Technical rept. 1 May 84-30 Sep 87,

Corporate Author : GEORGIA INST OF TECH ATLANTA SCHOOL OF MATERIALS ENGINEERING

Personal Author(s) : Antolovich, Stephen D

PDF Url : ADA189526

Report Date : Dec 1987

Pagination or Media Count : 102

Abstract : The objective of this study is to determine the effect of microstructural properties on the fatigue crack propagation (FCP) response of nickel base superalloys. This report describes the results of four experimental alloys containing various amounts of aluminum, titanium, and molybdenum. Chemistry, precipitate size, and grain size were varied to produce systematically controlled microstructures. The four alloys were characterized for chemical composition, microstructure, tensile properties, low cycle fatigue (LCF), and FCP resistance. The FCP tests were performed under constant load (increasing K) conditions in air at a stress ratio (R) of 0.1 and 0.8. Closure loads were measured with a clip gage, back-face strain gage, and a laser extensometer. Keywords: Fatigue crack propagation, Nickel base superalloys, Microstructure, Closure, Mismatch, Anti phase boundary.

Descriptors :   *NICKEL ALLOYS, *SUPERALLOYS, ALUMINUM, CHEMICAL COMPOSITION, CRACK PROPAGATION, EXTENSOMETERS, FATIGUE(MECHANICS), GRAIN SIZE, LASERS, LOADS(FORCES), MICROSTRUCTURE, MOLYBDENUM, STRAIN GAGES, TENSILE PROPERTIES, TITANIUM

Subject Categories : Fabrication Metallurgy

Distribution Statement : APPROVED FOR PUBLIC RELEASE