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Effects of Si content on the microstructure of modified-HP austenitic steels

Journal Article · · Materials Characterization; (United States)
;  [1];  [2]
  1. COPPE/UFRJ, Rio de Janeiro (Brazil)
  2. COPPE/UFRJ, Rio de Janiero (Brazil) Metallurgical Consulting Services Ltd., Saskatoon (Canada)
The microstructures of two centrifugally cast modified-HP steels with 1.97 wt% Nb and two different Si contents, 1.84 and 2.62 wt.%, were investigated using light and electron microscopy and x-ray diffraction. As noted in a previous study, the instability of the niobium carbide at elevated temperature is a particular feature of these alloys, exhibiting a partial transformation to a nickel-niobium silicide, G phase. The time-temperature-transformation diagram shows that the time to reach the nose of the transformation curve decreases with increase in silicon content. After aging at 900C for 1000h, the alloy with higher silicon content showed extensive secondary precipitation, and at the same time the niobium carbide particles were almost completely transformed to G phase.
OSTI ID:
6209580
Journal Information:
Materials Characterization; (United States), Journal Name: Materials Characterization; (United States) Vol. 30:4; ISSN 1044-5803; ISSN MACHEX
Country of Publication:
United States
Language:
English