In-situ high temperature stress analysis of Ti(C, N) coatings on functionally graded cemented carbides by energy dispersive synchrotron X-ray diffraction. (April 2016)

• Record Type: Journal Article
• Authors: García, José; Pinto, Haroldo; Ramos-Moore, Esteban; Espinoza, Carlos; Östby, Jonas; Coelho, Rodrigo
• Is Part Of: International journal of refractory metals & hard materials. Volume 56(2016:May)
• Page Start: 27
• Page End: 34
• Publication Date: 2016-04
• Subjects: In-situ high temperature stress analysis -- Energy dispersive X-ray diffraction -- Synchrotron radiation -- Scattering vector -- Thermal stress -- Ti(C, N) coatings -- Functionally graded cemented carbides -- EBSD -- Finite element modeling; Heat resistant alloys -- Periodicals; Refractory materials -- Periodicals; Metallography -- Periodicals; Alliages réfractaires -- Périodiques; Matériaux réfractaires -- Périodiques; Métallographie -- Périodiques; Heat resistant alloys; Metallography; Refractory materials; Periodicals; Electronic journals; 669.73
• DOI: 10.1016/j.ijrmhm.2015.12.001
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: We report on in-situ high temperature X-ray thermal stress analysis of chemically graded Ti(C, N) coatings deposited on functionally graded cemented carbide substrates by chemical vapor deposition. The in-situ analyses were performed by energy dispersive X-ray diffraction using synchrotron radiation. The samples were subjected to one individual thermal cycle from room temperature to 800 °C and cooled down to room temperature again. The stresses were determined using the sin 2 ψ method in the Ψ geometry combined with scattering vector measurements in order to unravel the compositional influences on the lattice strain distributions. It was found that the Ti(C, N) thin film presents a cycling residual stress behavior (tensile–compressive–tensile) connected to the temperature cycle. If top-blasting is applied on the thin film layer after the coating process, compressive stresses are generated. These compressive stresses induced by top-blasting are partially released after the high temperature thermal cycle. The functionalization of the cemented carbide substrate influences the level of stresses developed in the coating. The stress behavior as a function of temperature is discussed with the support of finite element modeling by introducing a bi-linear plasticity model to calculate strain relationships which is in agreement with the synchrotron measurements. Graphical abstract: Highlights: In-situ high temperature X-ray thermal stress analysis of CVD Ti(C, N) coatings Effect of functionally graded substrates on thermal cycle stress level Measured stresses below theoretical stresses indicating presence of microstructural defects FEM simulation combined with bi-linear plasticity model to fit measured strain relationships