A CONTRIBUTION TO THE STUDY OF POISSON RATIOS AND ELASTIC-CONSTANTS OF TIN, ZRN AND HFN

The elastic constants of the group IVB nitrides TiN, ZrN and HfN have been studied by X-ray residual stress measurements. Films of the nitrides were deposited onto stainless steel substrates by reactive sputtering and then vacuum annealed. They were studied using Cr K-alpha-radiation and the five available diffraction peaks (111) to (222). Poisson's ratios for bulk material are 0.30, 0.19 and 0.35 for the three nitrides respectively, indicating that the first and last are nearly isotropic which requires v to be 1/3. Values of the X-ray elastic constants and anisotropy factors were also derived.