Model for the maximum fraction of retained austenite in austempered ductile cast iron

2002 ◽  
Vol 333 (1-2) ◽  
pp. 60-66 ◽  
Author(s):  
M.A Yescas ◽  
H.K.D.H Bhadeshia
Keyword(s):  
Cast Iron ◽  
Retained Austenite ◽  
Ductile Cast Iron ◽  
Austempered Ductile Cast Iron

A Study of Austempered Ductile Cast Iron

1984 ◽  
Vol 34 ◽  
Author(s):  
J. D. Verhoeven ◽  
A. El Nagar ◽  
B. El Sarnagawa ◽  
D. P. Cornwell ◽  
F. Laabs
Keyword(s):  
Cast Iron ◽  
Retained Austenite ◽  
Lattice Parameter ◽  
Ductile Cast Iron ◽  
Austenitizing Temperature ◽  
Iron Matrix ◽  
Gamma Iron ◽  
Step Process ◽  
Austempered Ductile Cast Iron

ABSTRACTExperiments were carried out on unalloyed ductile cast iron to evaluate the % retained austenite (%RY) and its lattice parameter as a function of austenitizing time and temperature for austempering temperatures ranging from 270 to 420°C. Results are related to expected carbon levels in the gamma iron matrix at the austenitizing temperature. It is shown that the rate of austenitization can be described as a two step process and experiments demonstrate that 900°C austenitizatlon is complete after 8m. An 1100°C homogenizatdon has been shown to have a small effect upon %RY and rate of austenitization.

X-Ray Study on the Fatigue Fracture Surface of Austempered Ductile Cast Iron

1991 ◽  
Vol 35 (A) ◽  
pp. 503-510 ◽  
Author(s):  
Yoichi Kishi ◽  
Yukio Hirose ◽  
Zenjiro Yajima ◽  
Keisuke Tanaka
Keyword(s):  
Cast Iron ◽  
Fatigue Fracture ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Compact Tension ◽  
Ductile Cast Iron ◽  
Line Broadening ◽  
X Ray ◽  
Fracture Surfaces ◽  
Austempered Ductile Cast Iron

Austempered ductile cast iron (ADI) lias microstructures that consist of martensite and of retained austenite. ADI has very toughness compared with cast iron heat-treated differently. The retained austenite near fracture surfaces transforms to martensite when fracture occurs.In the present study, X-ray fraetography is applied to fatigue fracture surfaces of ADI. The fatigue tests were carried out on compact tension (CT) specimens. The volume fraction of retained austenite was measured quantitatively and the line broadening of X-ray diffraction profiles was measured on and beneath fatigue fracture surfaces. The depth of the plastic zone left on fracture surfaces was evaluated from line broadening. The results are discussed on the basis of fracture mechanics.

X-Ray Fractographic Study on Fatigue Fracture Surface of Ductile Cast Iron

1993 ◽  
Vol 37 ◽  
pp. 327-334
Author(s):  
Akira Suzuki ◽  
Yoichi Kishi ◽  
Zenjiro Yajima ◽  
Yukio Hirose
Keyword(s):  
Cast Iron ◽  
Fracture Surface ◽  
Fatigue Fracture ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Compact Tension ◽  
Fatigue Tests ◽  
Ductile Cast Iron ◽  
Fatigue Fracture Surface ◽  
X Ray

Austempered ductile cast iron (ADI) has composite microstructures, which are martensite/retained austenite structures. ADI has very large toughness compared to other ductile cast irons. After fracture, the retained austenite near the fracture surface will be transformed to martensite. In the present study, X-ray fractography is applied to fatigue fracture surface of ADI. The fatigue tests were carried out on compact tension (CT) specimens. The volume fraction of retained austenite was quantitatively measured on and beneath fatigue fracture surfaces. The plastic strain on the fracture surface was estimated from measuring the line broadening of X-ray diffraction profiles. The depth of the plastic zone left on fracture surface was evaluated from the distributions of the volume fraction of retained austenite. The results are discussed on the basis of fracture mechanics.

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