Continuous cavity nucleation and creep fracture

Journal Article · Sat Jan 01 04:00:00 EST 1983 · Scr. Metall.; (United States)

DOI:https://doi.org/10.1016/0036-9748(83)90065-0· OSTI ID:5531381

Dyson, B F

Intergranular creep fracture under the stress and temperature conditions experienced by components in service is generally acknowledged as resulting from nucleation and growth of intergranular cavities. Firstly, there seemed to be an approximately linear reciprocal relationship between time-to-fracture and minimum rate of creep deformation. Secondly, cavity growth by stress-directed flow of atoms was shown by Hull and Rimmer to lead to lifetime being inversely proportional to the maximum principal stress providing that all cavities initiated at the start of the test. Recently, it has been demonstrated that the boundary conditions imposed by Hull and Rimmer were unnecessarily restrictive and that more realistic ones result in cavity growth rates being proportional to strain rates. Nevertheless, there is an increasing body of experimental evidence on engineering alloys and also iron which indicates that cavities are not all nucleated in a short time interval, but are nucleated continuously. This paper collates the evidence for the continous nucleation of cavities, places this within the framework of creep fracture modelling and introduces a quantitative assessment of the likely errors of measurement. A model of cavity nucleation based on the stochastic nature of transgranular creep deformation is also discussed.

• Research Organization: Division of Materials Applications, National Physical Laboratory, Queens Road, Teddington, Middlesex, TW11 OLW
• OSTI ID: 5531381
• Journal Information: Scr. Metall.; (United States), Journal Name: Scr. Metall.; (United States) Vol. 17:1; ISSN SCRMB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
CAVITIES
CREEP
ELEMENTS
EQUATIONS
FRACTURE MECHANICS
GRAIN GROWTH
IRON
MECHANICAL PROPERTIES
MECHANICS
METALS
NUCLEATION
STRESS ANALYSIS
STRESS INTENSITY FACTORS
TEMPERATURE EFFECTS
TRANSITION ELEMENTS