Microstructural and crystallographic features of ausferrite in as-cast gray iron

Journal Article · Wed Sep 15 04:00:00 EDT 2004 · Materials Characterization

DOI:https://doi.org/10.1016/j.matchar.2004.07.008· OSTI ID:20748642

Ferry, M ^[1]; Xu, W ^[1]

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1. School of Materials Science and Engineering, University of New South Wales, Sydney NSW 2052 (Australia)

Ausferrite has been shown to form during casting of gray iron by carefully controlling the alloying additions Mo, Mn, Si and Cu and consists of an acicular ferrite constituent, termed bainitic ferrite ({alpha}{sub B}), which develops during continuous cooling as a coarse, feathery-type structure within the prior austenite ({gamma}) grains. Regardless of alloy composition, the ausferrite that forms in the microstructure during casting in volume fractions greater than {approx}0.1 was found to have a constant bainitic ferrite/retained austenite ratio ({alpha}{sub B}/{gamma}{approx}3). Electron backscatter diffraction (EBSD) in the scanning electron microscope has demonstrated that {alpha}{sub B} and {gamma} in ausferrite is related by the Kurdjumov-Sachs orientation relationship: {l_brace}111{r_brace}{sub {gamma}}//{l_brace}011{r_brace}{sub {alpha}} and <011>{sub {gamma}}//<111>{sub {alpha}} with a number of {alpha}{sub B} variants possible within a given austenite grain. This study confirms that the ausferrite generated in gray iron by direct casting has comparable microstructural and crystallographic characteristics to that produced in austempered gray and ductile irons.

• OSTI ID: 20748642
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Journal Issue: 1 Vol. 53; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AUSTENITE
BACKSCATTERING
CAST IRON
CASTING
CASTINGS
COOLING
CRYSTALLOGRAPHY
ELECTRON DIFFRACTION
FERRITE
IRON
MICROSTRUCTURE
ORIENTATION
SCANNING ELECTRON MICROSCOPY