The fractography of casting alloys

Journal Article · Sat Oct 01 04:00:00 EDT 1994 · Materials Characterization; (United States)

DOI:https://doi.org/10.1016/1044-5803(94)90048-5· OSTI ID:6823430

Powell, G W ^[1]

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1. Ohio State Univ., Columbus, OH (United States)

Several types of casting alloys were fractured using various loading modes (uniaxial tension, bending, impact, and torsion, and cyclic stressing), and the corresponding mechanical properties were determined. The unetched and etched fracture surfaces and the microstructures were examined using conventional techniques. The types of casting alloys that were the subjects f these investigations include gray iron, ductile iron, cast steel, and aluminum-base alloys (A380, A356, and 319). The fractographic studies have yielded these generalizations regarding the topography of the fracture surfaces. In the case of low-ductility alloys such as gray iron and the aluminum-base alloys, the tensile edge of a fracture surface produced by a stress system with a strong bending-moment component has a highly irregular contour, whereas the compressive edge of the fracture surface is quite straight and parallel to the bend axis. On the other hand, the periphery of a fracture surface produced by uniaxial tension has a completely irregular contour. The fracture surface produced by cyclic loading of a gray iron does not display any macroscopic evidence (such as a thumb nail) of the loading mode. However, the fracture surface of each of the other casting alloys displays clear, macroscopic evidence of failure induced by fatigue. The aluminum-base alloys fracture completely within the interdendritic region of the microstructure when subjected to monotonic loading by uniaxial tension or bending, whereas a fatigue crack propagates predominantly through the primary crystals of the microstructure.

• OSTI ID: 6823430
• Journal Information: Materials Characterization; (United States), Journal Name: Materials Characterization; (United States) Vol. 33:3; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ALUMINIUM ALLOYS
ALUMINIUM BASE ALLOYS
CRACK PROPAGATION
DYNAMIC LOADS
ELEMENTS
FRACTURE PROPERTIES
IRON
IRON ALLOYS
IRON BASE ALLOYS
MECHANICAL PROPERTIES
METALS
MICROSTRUCTURE
MORPHOLOGY
STEELS
SURFACE PROPERTIES
TRANSITION ELEMENTS