X-Ray Analysis of Creep-Induced Local Lattice Parameter Changes in a Monocrystalline Nickel-Base Superalloy

H. Mughrabi, H. Biermann, T. Ungar
1992 Superalloys 1992 (Seventh International Symposium)   unpublished
The r/+/-l a tt ice mismatch of specimens of the monocrystalline nickel-base superalloy SRR 99 has been measured by a high-resolution X-ray diffraction technique for the undeformed state and after high-temperature creep deformation. During creep deformation beyond the minimum creep rate (total strain w 0.5 %), the lattice mismatches, measured in and perpendicular to the [OOl] t s ress axis, respectively, undergo changes in opposite directions. This reflects the build-up of a complex
more » ... induced triaxial state of internal stress in the phases y and 7'. The overall resolved shear stresses which act in y' and y due to the combined action of the external and internal stresses are estimated and the conditions under which cutting of the y/-phase by dislocations should occur are discussed.
doi:10.7449/1992/superalloys_1992_599_608 fatcat:hpv7nv4rbjdrhflolupjanwzaa