Low cycle fatigue of PM/HIP astroloy

Conference · · TMS (The Metallurgical Society) Paper Selection; (USA)

OSTI ID:5450316

Choe, S J; Stoloff, N S; Duquette, D J ^[1]

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1. Rensselaer Polytechnic Institute, Troy, NY (USA)

Low cycle fatigue and creep-fatigue-environment interactions of PM/HIP Astrology were studied at 650 C and 725 C. Total strain range was varied from 1.5% to 2.7% at a frequency of 0.3Hz. Creep-fatigue tests were performed with 2 min. or 5 min. tensile hold times. All tests were run in high purity argon in an attempt to minimize environmental effects. Employing a tensile hold was more damaging than raising temperature by 75 C. Slopes of Coffin-Manson plots were nearly independent of temperature and hold time. Raising temperature from 650 C to 725 C did not change the transgranular (TG) crack propagation mode, whereas employing hold times caused TG+IG propagation. All samples displayed multiple fracture origins associated with inclusions located at the specimen surface; pre-existing pores did not affect fatigue crack initiation. Examination of secondary cracks showed no apparent creep damage. Oxidation in high purity argon appeared to be the major factor in LCF life degradation due to hold times.

• OSTI ID: 5450316
• Report Number(s): CONF-840909--
• Conference Information: Journal Name: TMS (The Metallurgical Society) Paper Selection; (USA) Journal Volume: 56
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ARGON
CHEMICAL REACTIONS
CRACK PROPAGATION
CRACKS
CREEP
ELEMENTS
FATIGUE
FLUIDS
FRACTURE MECHANICS
GASES
MECHANICAL PROPERTIES
MECHANICS
NONMETALS
OXIDATION
RARE GASES
STRAIN RATE
TEMPERATURE DEPENDENCE
TENSILE PROPERTIES
TIME DEPENDENCE