Temperature dependence of x-ray intensity profile FWHM of the γ' phase in the creep-deformed single crystal superalloy SC16

High-resolution diffraction using synchrotron x-ray radiation was applied to study gamma' precipitates with an L1(2) superlattice crystal structure in the single crystal superalloy SC16 after creep deformation at 1223 K with a creep strain of +/- 0.5% for tensile and compressive loads, respectively. The measurements of full width at half maximum (FWHM) of 00 1 and 100 gamma' superlattice reflections were performed at various temperatures from ambient temperature to 1173 K in vacuum. The experimental results revealed that the FWHM of both reflections decrease with increasing temperature. It is well-known that changes in particle size and lattice distortion in materials could lead to a variation of FWHM. The observed behaviour is discussed in the light of both the above-mentioned aspects. The decrease in the peak width is mainly attributed to the temperature dependence of the internal strain state.