CORRELATION OF HIGH TEMPERATURE CREEP AND RUPTURE DATA
The problem of correlating high temperature (T>0.45 T/sub m/) creep and rupture data has been considered in light of the most recent theoretical and experimental information. It is concluded that the deformation of metals and alloys at high temperatures is diffusion controlled and the activation energy is given by the activation energy for self-diffusion of the base metal or diffusion of the alloying constituents. This activation energy should be independent of stress. For low stresses, the dislocation theory predicts a power stress law with an exponent of approximately 4. Experimentally a hyperbolic sine stress law of the form sinh STA sigma / sigma /sub 0/(T)!/sup n/ is very frequently observed over the entire stress range. The change in structure during creep is difficult to predict. It is frequently assumed that it is constant at the minimum creep rate or at the time of rupture. In many cases this appears to be a reasonable assumption, if the stress constant sigma /sub 0/ is taken as a function of temperature. The equations most frequently employed for correlating creep and rupture data are at variance with one or more of these conclusions, and hence can lead to serious error when used for extrapolating short time data to long times. An equation is presented which correlated high temperature creep and rupture data. (auth)
- Research Organization:
- Westinghouse Electric Corp., Pittsburgh
- NSA Number:
- NSA-14-004564
- OSTI ID:
- 4216083
- Journal Information:
- Journal of Basic Engineering (U.S.) Divided into J. Eng. Mater. Technol. and J. Fluids Eng., Vol. Vol: 81; Other Information: Orig. Receipt Date: 31-DEC-60
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
Calibration of CDM-Based Creep Constitutive Model Using Accelerated Creep Test (ACT) Data
Stress relaxation of braze joints