Abstract:
This paper
presents the quantitative relationship between ductile-brittle
transition temperature, TC, and the size of cleavage fracture
unit, dr, in steels 10, 20, 35, 45, 55, 70, T8A and 38CrA. The
following equation is obtained. It was discovered that the
cleavage fracture unit is a material's constant, it has no
relation to the shape or notch of specimen, form of notch, and
experimental conditions. The process of ductile-brittle
transition is a process of variation of the quantity of cleavage
fracture units. Therefore, the size of cleavage fracture unit
may be considered as a characteristic parameter of microfracture
during ductile-brittle transition of materials and as a basis
for diagnosis of cold short fracture.
Key words:
Steel Ductile-brittle transition
Microfracture Diagnosis
* This project is supported by National Natural Science Foundation of
China, Funds of State Key Laboratory for Fatigue and Fracture of
Materials and Aeronautical Science Foundation. Manuscript received on
December 25, 1991; revised manuscript May 20, 1992
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