Premium
Extension of a constitutive model describing the inelastic behaviour of a precipitation hardened alloy
Author(s) -
Reichert Birgit
Publication year - 1999
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199905610
Subject(s) - alloy , carbide , precipitation , creep , metallurgy , thermodynamics , ultimate tensile strength , chemistry , materials science , physics , meteorology
The one internal variable model by Kocks, Mecking and Estrin has been applied for the description of the hot tensile and creep behaviour under constant loading conditions of Alloy 800H, a carbide precipitation strengthened high temperature alloy. The model was extended by incorporating an expression for a mean free path of mobile dislocations which depends on the kinetics of the precipitation and ripening process of the secondary carbides. Microscopy and mechanical data for three different heats of Alloy 800H at 900°C were evaluated to enable comparison between calculations using the extended model and experimental data. Difficulties were caused by the complex precipitation behaviour of the alloy in which both larger carbides of type M 23 C 6 and smaller ones of type M(C,N) are formed in the investigated range of temperature. Although the microstructural data available is not sufficient for a reliable quantitative description of the evolution with time of the average carbide spacing a qualitative agreement between calculations and mechanical data gives a preliminary verification of the developed extended model.