X-RAY-DIFFRACTION STUDY OF THE SUBSTRUCTURE MODIFICATION INDUCED BY RESIDUAL-STRESSES DURING THE DEPOSITION PROCESS OF 304L STAINLESS-STEELFILMS

X-ray diffraction using the ''sin(2) psi method'' has been used to stu dy the influence of the deposited thickness on the microstructural and mechanical state of 304L stainless steel films. The thin films are fo und to be in a high compressive stress state (2-3 GPa). Even though th e microstructural state in films is identical, the film morphology is different according to the deposited thickness; when this increases fr om 175 to 500 nm, the film morphology evolves from an isotropic distri bution to a columnar structure of grains. This sub-structure modificat ion is clearly evidenced by X-ray diffraction measurements. The explan ation of this modification is quite simple: the columnar structure pro vides tensile stresses which induce a stress relaxation in this part o f the film.