Accession Number : ADA319770

Title :   Internal Stresses, Texture, and Anisotropy in High-Contraction Electroplated Chromium Coatings.

Descriptive Note : Final rept.,

Corporate Author : ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS

Personal Author(s) : Lee, S. L. ; Capsimalis, G. P.

PDF Url : ADA319770

Report Date : SEP 1996

Pagination or Media Count : 26

Abstract : Internal residual stresses in refractory coatings of the bore cause cracking, flaking, peeling, and failure of the coatings and substrate. Strong fiber texture, perfect in-plane azimuthal symmetry, low single-crystal anisotropy, and high-surface tensile residual stresses were observed in high-contraction chromium on steel. The conventional d-square of sin(psi) method fails in the evaluation of residual stress if the existence of texture is not taken into account. Elastic moduli were evaluated from single-crystal elastic constants. Two methods were developed to extract residual stresses in textured chromium coatings: (1) A new matlab matrix inversion method using a single family of reflections. The method allows calculation of residual stress and unstrained lattice parameter in textured cubic materials. (2) A Hill-Neerfeld model assuming elastic isotropy. This is a d-square of sin(psi) method adapted to multiple families of reflections.

Descriptors :   *PROTECTIVE COATINGS, *CHROMIUM, *ELECTROPLATING, ARMY RESEARCH, STRESS ANALYSIS, CRYSTAL LATTICES, TENSILE STRESS, CRACKING(FRACTURING), MODULUS OF ELASTICITY, STAINLESS STEEL, SINGLE CRYSTALS, METAL COATINGS, SUBSTRATES, ANISOTROPY, RESIDUAL STRESS, FAILURE(MECHANICS), FRICTION, MELTING POINT, THERMAL STRESSES, HARDNESS, DIFFRACTION ANALYSIS, EROSION RESISTANCE, REFRACTORY COATINGS.

Subject Categories : Coatings, Colorants and Finishes
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE