The effect of testing temperature on fracture toughness of austempered ductile iron

Citation
Ch. Hsu et al., The effect of testing temperature on fracture toughness of austempered ductile iron, MET MAT T A, 32(2), 2001, pp. 295-303
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science",Metallurgy
Journal title
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
ISSN journal
1073-5623 → ACNP
Volume
32
Issue
2
Year of publication
2001
Pages
295 - 303
Database
ISI
SICI code
1073-5623(200102)32:2<295:TEOTTO>2.0.ZU;2-A
Abstract
The effect of testing temperature (-150 degreesC, 25 degreesC, and +150 deg reesC) on the fracture toughness of austempered ductile iron (ADI) was stud ied. Specimens were first austenitized at 900 degreesC for 1.5 hours and th en salt-bath quenched to 360 degreesC or 300 degreesC, for 1, 2, or 3 hours of isothermal holding before cooling to room temperature. The resulting ma trices of the iron were of upper-ausferrite and lower-ausferrite. It was fo und that raising the testing temperature to 150 degreesC from ambient impro ved the fracture toughness by 18, 30, and 7 pct for the as-cast/lower-ausfe rrite ADI/upper-ausferrite ADI, respectively. Lowering the testing temperat ure to -150 degreesC produced a decrease of -15, -35, and -48 pct. Optical microscopy, X-ray diffraction analysis, and scanning electron microscopy (S EM) fractography were applied to correlate the toughness variation with tes ting temperatures.