Elevated Temperature Low Cycle Fatigue of Nickel Base Superalloys in the Conventionally Cast, Directionally Solidified and Single Crystal Forms

摘要

High temperature low cycle fatigue (LCF) has been studied for directionally solidified (DS) and conventionally cast (CC) Rene' 80. For the conventionally cast material testing was carried out on smooth bars over the temperature range 75 F (24 C) to 1800 F (982 C). It was found that at low temperatures slip was planar and carbides acted as crack initiation sites. In correspondence with the importance of carbides on the fatigue life it was found that life cosrrelated best with total strain range (as opposed to plastic strain range).