Some observations on the fracture of austempered ductile iron

Journal Article · Fri Jul 15 00:00:00 EDT 1994 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(94)90164-3· OSTI ID:7108748

Fan, Z K; Smallman, R E ^[1]

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1. Univ. of Birmingham (United Kingdom). School of Metallurgy and Materials

There is extensive work on the fracture of steel with ferrite or/and austenite structure, but little on crack propagation in austempered ductile iron (ADI) whose microstructure also comprises austenite and ferrite (in the form of bainitic ferrite) but with graphite nodules in the matrix. Because of its good combination of wear resistance and toughness, and its low density and low cost (compared with forge steel), ADI has been widely used for various kinds of engineering components, such as gears, crankshafts, vehicle components, sprockets, cutting and digging tools etc. The matrix of ADI can withstand a certain amount of deformation before fracture during tensile or impact testing; for example, the elongation of ADI (grade 1050/700/7 to ASTM Standard) can reach 7--10% during tensile testing. However, the graphite nodules in the matrix cannot deform and hence are barriers to matrix deformation and give rise to crack initiation. In addition, carbides may precipitate in the bainitic ferrite laths or at the ferrite/austenite interfaces and these may also influence the fracture of ADI and produce characteristic features.

• OSTI ID: 7108748
• Journal Information: Scripta Metallurgica et Materialia; (United States), Journal Name: Scripta Metallurgica et Materialia; (United States) Vol. 31:2; ISSN SCRMEX; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
CARBON
CRACK PROPAGATION
DATA
ELECTRON MICROSCOPY
ELEMENTAL MINERALS
ELEMENTS
EXPERIMENTAL DATA
FRACTURE PROPERTIES
GRAPHITE
INFORMATION
IRON
MECHANICAL PROPERTIES
METALS
MICROSCOPY
MICROSTRUCTURE
MINERALS
NONMETALS
NUMERICAL DATA
SCANNING ELECTRON MICROSCOPY
TRANSITION ELEMENTS