Crystallographic Initiation of Nickel-Base Superalloy IN100 at RT and 538�C Under Low Cycle Fatigue Conditions

Abstract

The crystallographic plane of IN100 at the initiation region of fracture surfaces under low cycle fatigue (LCF) conditions at RT and elevated temperature was identified. At RT fatigue cracks initiated on the {111} plane and at elevated temperature on the {001} plane. The initiation plane index was initially determined by investigating the shape in the matrix of fracture surfaces around crack initiation sites and finally verified by orientation image microscopy (OIM). An OIM scan on a sample of original material indicated that local texture might promote a fatigue crack to reach a critical crack size.