Title: FEM analysis of crystallisation residual stresses in composite Ni-P(B4C) films

Authors: M. Boniardi, G.C. Martinelli, B. Bozzini, R. Vitali

Addresses: Dipartimento di Meccanica, Politecnico Di Milano, Piazza. L. da Vinci 32, I-20133 Milano, Italy. Dipartimento di Meccanica, Politecnico Di Milano, Piazza. L. da Vinci 32, I-20133 Milano, Italy. Dipartimento di Chimica Fisica Applicata, Politecnico Di Milano, Via Mancinelli 7, I-20131 Milano, Italy. HKS Italia S.r.l.,Viale Certosa 1, I-20149 Milano, Italy

Abstract: The thermo-mechanical behaviour of supported MMC Ni-P(B4C) coatings was studied with a FEM modelling and experimental methods. Crystallisation residual stresses in the Ni-P matrix were computed by means of a sub-model technique and were measured with two independent methods X-ray diffractometry and Vickers indentation. The main conclusions of the FEM simulation are: (i) the matrix is in a tensile stress status and the dispersoid in a compressive one; (ii) the matrix is plasticised; (iii) no appreciable stress gradients as a function of coatings depth are pre- sent, except for slight (~5%) variations at the coating surface and at the coating-substrate interface. Experimental residual stresses are consistent and in quantitative agreement with maximum tensile stress values from FEM simulations. The stress distribution predicted by FEM was verified with crack path observations by SEM.

Keywords: residual stresses; Ni-P coatings; composite materials; FEM analysis.

DOI: 10.1504/IJMPT.2000.001236

International Journal of Materials and Product Technology, 2000 Vol.15 No.1/2, pp.63-77

Published online: 01 Jul 2003 *

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