Comparison of Damage Processes in two Austenitic Steels Under Thermal Cycling and Creep Conditions
Processes of thermal cycling in materials are difficult to analyse because of complexity of the phenomena involved. The aim of the paper was to check the assumption that there is some similarity in failure mechanisms occurring under thermal cycling and stationary creep conditions. To this end deformation processes up to failure were analysed in various austenitic steels. The experiments were carried out on axially loaded cylindrical specimens made of austenitic steels. The specimens were tested in isothermal creep at temperatures 1173, 1123, 1073, 1023K and under thermal cycling conditions over the range 573-1173 K using three different thermal cycles: a saw-toothed and two trapezoidal ones. The investigation was aimed at assessing the contributions of creep and cyclic deformation to failure processes induced by various modes of thermal loading. The Monkman-Grant failure criterion was used to give a relationship between time to failure and steady deformation rate.
References
R.ŻUCHOWSKI, Analysis of failure process under conditions of thermal fatigue [in Polish], Technical University of Wrocław, Wrocław 1986.
A.WEROŃSKI, Thermal fatigue of metals, WNT, Warszawa 1983.
Z.ORŁOŚ, Thermal cycling, Wyd. Nauk. PWN, Warszawa 1991.
R.ŻUCHOWSKI, N.BUBA, Assessment of durability under conditions of thermal cycling on the basis of the results obtained in creep, Res Mechanica, 5, 4, 317-3221 1982.
R.ŻUCHOWSKI, Specific strain work as both a failure criterion and material damage measure, Res Mechanica, 27, 4, 309-322, 1989.
F.C.MONKMAN, N.J.GRANT, An empirical relationship between rupture life and minimum creep rate in creep-rupture test, ASTM Preprint 72, Annual Meeting, June 17, 1956.
R.ŻUCHOWSKI, L.KORUSIEWICZ, Acoustic emission as a measure of material damage under thermal cycling, J.Acoustic Emission, 2, 4, 272-274, 1983.
C.DEGALLAIX, O.KORN, G.PLUVINAGE, Lifetime prediction on Cr-Mo-V and 316L steels under thermal and mechanical cycling, Fatigue and Fracture of Engng. Materials and Structures, 13, 5, 473-485, 1990.
D.A.BOISMIER, H.SEHITOGLU, Thermo-mechanical fatigue of MAR-M241. Part 1. Experiments, Trans. ASME J. Engng. Materials and Technology, 112, 1, 68-79, 1990.
H.SEHITOGLU, D.A.BOISMIER, Thermo-mechanical fatigue of MAR-M247. Part 2. Life prediction, Trans. ASME J. Engng. Materials and Technology, 112, 1, 80-89, 1990.
R.ŻUCHOWSKI, Effect of stress state type on deformation process of austenitic steel under thermal cycling conditions, Intern. J. Pressure Vessels and Piping, 46, 279-288, 1991.
G.R.HALFORD, S.S.MANSON, Life prediction of thermal-fatigue using strain range partitioning, Thermal Fatigue of Materials and Components, ASTM STP 612, 239-254, 1976.