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The mosaic structure of Fe‐3% Si Alloy Single Crystals Prepared by Floating Zone Melting at Different Growing Rates
Author(s) -
Kadečková S.,
Šesták B.
Publication year - 1969
Publication title -
kristall und technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0023-4753
DOI - 10.1002/crat.19690040208
Subject(s) - misorientation , substructure , materials science , dislocation , crystallography , supercooling , etching (microfabrication) , crystal (programming language) , alloy , single crystal , zone melting , growth rate , condensed matter physics , composite material , geometry , microstructure , chemistry , layer (electronics) , physics , structural engineering , mathematics , computer science , grain boundary , engineering , thermodynamics , programming language
Dislocation substructure of Fe‐3% Si alloy single crystals of 13 mm in diameter, prepared at floating zone velocities of 0.7; 1.5; 3 and 5 cmh 1 , was studies. The dislocation substructure was rendered visible by etching and by Berg‐Barrett X‐ray topographic method. Mosaic blocks of 1 to 3 mm size, the misorientation angles lower than 1 minute of arc and the dislocation density inside the blocks 1 to 5 · 10 4 cm 2 are observed in single crystals up to 200 mm long, grown at the rate of 0.7 cm h 1 . At higher growth rates the mosaic blocks are smaller and their misorientation increases in the growth direction. In all cases higher misorientation angles and smaller blocks near the crystal surface are observed. The thermal stresses are an important source of dislocations and their influence increases with the rate of crystal growth. Changes of the silicon concentration gradients caused by constitutional supercooling are another important source of dislocations especially at higher growth rates.