CREEP EQUATIONS FOR HIGH-TEMPERATURE ALLOYS ON THE BASIS OF A PARAMETRIC ASSESSMENT OF MULTI-HEAT DATA

For the design of high temperature components creep equations are nece ssary. These describe the deformation behaviour of the material type u sed over its whole application range. The method of developing such an equation is demonstrated for the example of alloy G-NiCo 15 Cr 10 Al 6 TiMo (Alloy 100). As a basic requirement, a multi-heat assessment of time to specific strain is performed with the aid of a time temperatu re parameter procedure. In this way optimum correlated master curves a re generated for the whole range of permanent strain and rupture. From these curves mean creep curves for the material type can be determine d by minimal further smoothing. On the basis of these creep curves a m odified Garofalo equation with initial plastic strain as well as prima ry, secondary and tertiary strain can be established to describe the c reep behaviour of Alloy 100. Additionally, an equation for the time te mperature dependent contraction of this alloy can be developed. These equations form a useful tool for the calculation of high temperature c omponents with the finite element method.