Investigation of the microstructure and strength in G115 steel with the different concentration of tungsten during creep test

Published on Mar 1, 2019in Materials Characterization3.562
· DOI :10.1016/J.MATCHAR.2019.01.015
Zhen Liu6
Estimated H-index: 6
(USTB: University of Science and Technology Beijing),
Zhengdong Liu2
Estimated H-index: 2
+ 1 AuthorsZhengzong Chen3
Estimated H-index: 3
Sources
Abstract
Abstract The microstructure and creep strength of three G115 specimens, 9 Cr-(2.3, 2.6, 3.0)W-3 Co (wt%), were investigated after creep test at 650 °C under 120 MPa using field emission transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction, and Ultra-high temperature confocal microscope, focusing on martensitic lath, precipitates, dislocation densities and the block boundaries. The results show that the coarsening rates of the laths and Laves phase particles increased with the increase in W concentration during creep test. The majority of cavities was nucleated at high angle boundaries where many Laves phase particles existed in the neck portions of the specimens. The types of the crack were different among the three steels: the cracks in 2.3 W G115 steel specimens mainly resembled “wedge crack”, while the cracks in 2.6 W and 3.0 W G115 steel specimens mainly resembled “flower crack”. The 2.3 W G115 steel has the longest creep rupture life.
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