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Title: Microstructural characteristics and mechanism of toughness improvement of laser and electron-beam welds of V-4Cr-4Ti following postwelding heat-treatment

Abstract

The authors are conducting a program to develop an optimal laser welding procedure for large-scale fusion-reactor structural components to be fabricated from vanadium-base alloys. Microstructural characteristics were investigated by optical microscopy, X-ray diffraction, transmission electron microscopy, and chemical analysis to provide an understanding of the mechanism of the drastic improvement of impact toughness of laser and electron-beam (EB) welds of V-4Cr-4Ti following postwelding annealing at 1000{degrees}C. Transmission electron microscopy (TEM) revealed that annealed weld zones were characterized by extensive networks of fine V(C,O,N) precipitates, which appear to clean away O, C, and N from grain matrices. This process is accompanied by simultaneous annealing-out of the dense dislocations present in the weld fusion zone. It seems possible to produce high-quality welds under practical conditions by controlling and adjusting the cooling rate of the weld zone by some innovative method to maximize the precipitation of V(C,O,N).

Authors:
; ; ;  [1]
  1. Argonne National Laboratory, IL (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
OSTI Identifier:
415826
Report Number(s):
DOE/ER-0313/20
ON: DE97000700; TRN: 97:001880
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Oct 1996; Related Information: Is Part Of Fusion materials semiannual progress report for the period ending June 30, 1996; PB: 358 p.
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 70 PLASMA PHYSICS AND FUSION; VANADIUM BASE ALLOYS; ELECTRON BEAM WELDING; LASER WELDING; TITANIUM ALLOYS; CHROMIUM ALLOYS; WELDED JOINTS; MICROSTRUCTURE; FLEXURAL STRENGTH; PROGRESS REPORT; ANNEALING

Citation Formats

Chung, H. M., Park, J. H., Gazda, J., and Smith, D. L. Microstructural characteristics and mechanism of toughness improvement of laser and electron-beam welds of V-4Cr-4Ti following postwelding heat-treatment. United States: N. p., 1996. Web. doi:10.2172/415826.
Chung, H. M., Park, J. H., Gazda, J., & Smith, D. L. Microstructural characteristics and mechanism of toughness improvement of laser and electron-beam welds of V-4Cr-4Ti following postwelding heat-treatment. United States. https://doi.org/10.2172/415826
Chung, H. M., Park, J. H., Gazda, J., and Smith, D. L. 1996. "Microstructural characteristics and mechanism of toughness improvement of laser and electron-beam welds of V-4Cr-4Ti following postwelding heat-treatment". United States. https://doi.org/10.2172/415826. https://www.osti.gov/servlets/purl/415826.
@article{osti_415826,
title = {Microstructural characteristics and mechanism of toughness improvement of laser and electron-beam welds of V-4Cr-4Ti following postwelding heat-treatment},
author = {Chung, H. M. and Park, J. H. and Gazda, J. and Smith, D. L.},
abstractNote = {The authors are conducting a program to develop an optimal laser welding procedure for large-scale fusion-reactor structural components to be fabricated from vanadium-base alloys. Microstructural characteristics were investigated by optical microscopy, X-ray diffraction, transmission electron microscopy, and chemical analysis to provide an understanding of the mechanism of the drastic improvement of impact toughness of laser and electron-beam (EB) welds of V-4Cr-4Ti following postwelding annealing at 1000{degrees}C. Transmission electron microscopy (TEM) revealed that annealed weld zones were characterized by extensive networks of fine V(C,O,N) precipitates, which appear to clean away O, C, and N from grain matrices. This process is accompanied by simultaneous annealing-out of the dense dislocations present in the weld fusion zone. It seems possible to produce high-quality welds under practical conditions by controlling and adjusting the cooling rate of the weld zone by some innovative method to maximize the precipitation of V(C,O,N).},
doi = {10.2172/415826},
url = {https://www.osti.gov/biblio/415826}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Oct 01 00:00:00 EDT 1996},
month = {Tue Oct 01 00:00:00 EDT 1996}
}