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Effect of withdrawal rate transition on microstructural features of a single crystal Ni‐based superalloy
Author(s) -
Sadeghi Fazlollah,
Kermanpur Ahmad,
Heydari Davoud,
Bahmani Majid
Publication year - 2017
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201700012
Subject(s) - materials science , electron backscatter diffraction , superalloy , crystal (programming language) , diffraction , scanning electron microscope , growth rate , optical microscope , crystallography , composite material , microstructure , chemistry , optics , geometry , physics , mathematics , computer science , programming language
The effect of withdrawal rate transition during Bridgman directional solidification on microstructural aspects of a single crystal Ni‐based superalloy was investigated under both constant and changing withdrawal regimes. Variations of primary and secondary dendrite arm spacing (PDAS and SDAS, respectively) and crystal orientation were investigated using optical microscopy and electron backscattered diffraction (EBSD) techniques. The results showed a gradual decreasing trend in PDAS and SDAS by sudden increasing of withdrawal rate. Changes on PDAS was quantified as history‐dependent such that for a given secondary withdrawal rate, a higher PDAS was found for a lower initial withdrawal rate. The withdrawal rate transition showed a direct influence on crystal orientation.