TUTCRIS Research Portal

TY - JOUR

T1 - Microstructure-based thermo-mechanical modelling of thermal spray coatings

AU - Bolelli, Giovanni

AU - Candeli, Alessia

AU - Koivuluoto, Heli

AU - Lusvarghi, Luca

AU - Manfredini, Tiziano

AU - Vuoristo, Petri

PY - 2015/5/15

Y1 - 2015/5/15

N2 - This paper demonstrates how microstructure-based finite element (FE) modelling can be used to interpret and predict the thermo-mechanical behaviour of thermal spray coatings. Validation is obtained by comparison to experimental and/or literature data.Finite element meshes are therefore constructed on SEM micrographs of high velocity oxygen-fuel (HVOF)-sprayed hardmetals (WC-CoCr, WC-FeCrAl) and plasma-sprayed Cr2O3, employed as case studies. Uniaxial tensile tests simulated on high-magnification micrographs return micro-scale elastic modulus values in good agreement with depth-sensing Berkovich micro-indentation measurements. At the macro-scale, simulated and experimental three-point bending tests are also in good agreement, capturing the typical size-dependency of the mechanical properties of these materials. The models also predict the progressive stiffening of porous plasma-sprayed Cr2O3 due to crack closure under compressive loading, in agreement with literature reports.Refined models of hardmetal coatings, accounting for plastic behaviours and failure stresses, predict crack initiation locations as observed by indentation tests, highlighting the relevance of stress concentrations around microstructural defects (e.g. oxide inclusions).Sliding contact simulations between a hardmetal surface and a small spherical asperity reproduce the fundamental processes in tribological pairings. The experimentally observed "wavy'' morphologies of actual wear surfaces are therefore explained by a mechanism of micro-scale plastic flow and matrix extrusion. (C) 2015 Elsevier Ltd. All rights reserved.

AB - This paper demonstrates how microstructure-based finite element (FE) modelling can be used to interpret and predict the thermo-mechanical behaviour of thermal spray coatings. Validation is obtained by comparison to experimental and/or literature data.Finite element meshes are therefore constructed on SEM micrographs of high velocity oxygen-fuel (HVOF)-sprayed hardmetals (WC-CoCr, WC-FeCrAl) and plasma-sprayed Cr2O3, employed as case studies. Uniaxial tensile tests simulated on high-magnification micrographs return micro-scale elastic modulus values in good agreement with depth-sensing Berkovich micro-indentation measurements. At the macro-scale, simulated and experimental three-point bending tests are also in good agreement, capturing the typical size-dependency of the mechanical properties of these materials. The models also predict the progressive stiffening of porous plasma-sprayed Cr2O3 due to crack closure under compressive loading, in agreement with literature reports.Refined models of hardmetal coatings, accounting for plastic behaviours and failure stresses, predict crack initiation locations as observed by indentation tests, highlighting the relevance of stress concentrations around microstructural defects (e.g. oxide inclusions).Sliding contact simulations between a hardmetal surface and a small spherical asperity reproduce the fundamental processes in tribological pairings. The experimentally observed "wavy'' morphologies of actual wear surfaces are therefore explained by a mechanism of micro-scale plastic flow and matrix extrusion. (C) 2015 Elsevier Ltd. All rights reserved.

KW - Thermal spray

KW - Coatings

KW - Finite element simulation

KW - Microstructure based model

KW - Elastic properties

KW - Contact simulation

KW - METAL-MATRIX COMPOSITES

KW - DUAL-PHASE STEEL

KW - BARRIER COATINGS

KW - ALUMINA COATINGS

KW - ELASTIC-MODULUS

KW - BEHAVIOR

KW - MECHANISMS

KW - INDENTATION

KW - CONDUCTIVITY

KW - SIMULATION

U2 - 10.1016/j.matdes.2015.02.014

DO - 10.1016/j.matdes.2015.02.014

M3 - Article

VL - 73

SP - 20

EP - 34

JO - Materials and Design

JF - Materials and Design

SN - 0264-1275

ER -