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MRT letter: Extended depth from focus reconstruction method for stretch zone measurement in 15‐5PH steel
Author(s) -
De Oliveira Caltabiano Pietro Carelli Reis,
Rosa Paulo Henrique Santos,
De Campos Kamila Amato,
De Oliveira Hein Luis Rogerio
Publication year - 2012
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.22042
Subject(s) - depth of field , materials science , brightness , microscopy , optics , focus (optics) , confocal , scanning electron microscope , optical microscope , microscope , fracture (geology) , resolution (logic) , depth of focus (tectonics) , geology , computer science , artificial intelligence , composite material , physics , paleontology , subduction , tectonics
The stretch zone width (SZW) data for 15‐5PH steel CTOD specimens fractured at −150°C to + 23°C temperature were measured based on focused images and 3D maps obtained by extended depth‐of‐field reconstruction from light microscopy (LM) image stacks. This LM‐based method, with a larger lateral resolution, seems to be as effective for quantitative analysis of SZW as scanning electron microscopy (SEM) or confocal scanning laser microscopy (CSLM), permitting to clearly identify stretch zone boundaries. Despite the worst sharpness of focused images, a robust linear correlation was established to fracture toughness ( K C ) and SZW data for the 15‐5PH steel tested specimens, measured at their center region. The method is an alternative to evaluate the boundaries of stretched zones, at a lower cost of implementation and training, since topographic data from elevation maps can be associated with reconstructed image, which summarizes the original contrast and brightness information. Finally, the extended depth‐of‐field method is presented here as a valuable tool for failure analysis, as a cheaper alternative to investigate rough surfaces or fracture, compared to scanning electron or confocal light microscopes. Microsc. Res. Tech. 75:1155–1158, 2012. © 2012 Wiley Periodicals, Inc.