Residual stress gradients in α-Al2O3 hard coatings determined by pencil-beam X-ray nanodiffraction: The influence of blasting media

Tkadletz, Michael; Keckes, Jozef; Schalk, Nina; Krajinović, Ivan; Burghammer, Manfred; Czettl, Christoph; Mitterer, Christian

doi:10.1016/j.surfcoat.2014.12.028

Cited by 41 publications

(14 citation statements)

References 38 publications

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“…The coating deposition was carried out in an industrial scale SuCoTec SCT600TH CVD plant. Subsequent to the deposition, the coated inserts were subjected to a wet blasting treatment with the central aim of changing the residual stress state of coating and substrate from tensile to compressive as summarised in our previous work [14].…”

Section: Experiments and Methodologymentioning

confidence: 99%

20 Hz synchrotron X-ray diffraction analysis in laser-pulsed WC-Co hard metal reveals oscillatory stresses and reversible composite plastification

Gruber

Kiefer

Rössler

et al. 2019

International Journal of Refractory Metals and Hard Materials

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The lifetime of WC-Co inserts used in cutting processes, such as milling, is limited by millisecond temperature and mechanical pulses, which occur as a result of interrupted tool-workpiece contact, thermal fatigue and wear. In the current work, synchrotron X-ray diffraction (XRD) was used in conjunction with a pulsed laser heating setup to characterise the time-dependent development of stresses and microstructure in locally irradiated WC-Co inserts coated by chemical vapour deposition with 6.5 and 3.5 µm thick TiCN and α-Al2O3 films, respectively. Diffraction data from the WC-Co phase were used to evaluate the time and temperature-dependent evolution of in-plane stresses, thermal strains and integral breadths of WC diffraction peaks in experiments with a single and five successive laser shocks applied within 2.2 and 20 seconds, respectively, using a laser spot diameter of ~5.8 mm and an X-ray beam size of 1 × 1 mm 2. The laser heating induces the formation of compressive stresses in the inserts' substrates. Above a temperature of ~750°C, at the onset of WC-Co composite plastification, compressive stresses relax and then vanish in WC at the maximal applied temperature of ~1300°C, followed by the build-up of tensile stresses. The applied cyclic heating up and cooling down led to the repetitive formation of compressive and tensile stresses, with temperature dependencies oscillating with the number of applied laser pulses. The observed relatively high tensile stress level of ~1100 MPa in WC was a consequence of the stabilising function of the coating, which hindered the initiation of surface hot cracks and stress relaxation. The stress evolution was coupled with changes in XRD peak broadening, which however strongly depended on the particular hkl reflections and showed oscillatory behaviour within a single temperature cycle. In summary, the unique diffraction setup revealed stress levels and provides insight into the WC-Co composite plastification mechanism governing the stress build-up and relaxation in locally thermo-shocked WC-Co inserts at millisecond time resolution.

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Section: Experiments and Methodologymentioning

confidence: 99%

20 Hz synchrotron X-ray diffraction analysis in laser-pulsed WC-Co hard metal reveals oscillatory stresses and reversible composite plastification

Gruber

Kiefer

Rössler

et al. 2019

International Journal of Refractory Metals and Hard Materials

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“…The reported slopes result from a linear fit of the experimental data. [81] Complementary to XRD, electron microscopy techniques, such as the above mentioned TEM or SEM in combination with electron backscatter diffraction (EBSD) are commonly utilized to investigate the microstructural evolution of the samples. [79] Next to the substrate/coating interface, the TiN base-layer exhibits a rather small grain size, which increases with increasing coating thickness, typical for competitive growth.…”

Section: Characterization Of Microstructure Texture Domain Size Anmentioning

confidence: 99%

Complementary High Spatial Resolution Methods in Materials Science and Engineering

Paris

Lang

et al. 2017

Adv Eng Mater

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REVIEWThis review features the potential of modern high spatial resolution methods in materials science and engineering by presenting a selection of scientific examples covering bulk materials, as well as hard coatings, semiconductors, and mesoporous thin films. Complementary techniques are employed to study microstructure and/or texture and stresses in multiphase Mo-, Al-, and Mg-base alloys, in several nitride-and boride-based hard coatings, in silicon, as well as in mesoporous silica films. Although far from being comprehensive, the chosen examples aim at underlining the importance of modern electron microscopy based methods and of scattering/diffraction techniques at large scale neutron and synchrotron radiation facilities for modern materials research. In addition, atom probe tomography, Raman scattering and atomic force microscopy are also highlighted.

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“…Decomposition of the cutting insert X-ray diffraction pattern ( = 10 , È = 0) by simultaneous refinement in all measured È directions {0, 45, 90 }: pattern (open circles), decomposition (green line), difference (grey line), -Al 2 O 3 (blue line), TiCN (red line), GOF = 1.13. corresponding sample was scrutinized within the project 'residual stress gradients in -Al 2 O 3 hard coatings' (Tkadletz et al, 2015). Employing cross-sectional synchrotron X-ray nanodiffraction, the local residual stress profile (Fig.…”

Section: Figurementioning

confidence: 99%

Pattern decomposition for residual stress analysis: a generalization taking into consideration elastic anisotropy and extension to higher-symmetry Laue classes

2017

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The residual stress state of ion‐conducting layers (yttria stabilized zirconia) and protective hard coatings (α‐aluminium oxide, titanium carbonitride) was investigated using X‐ray diffraction techniques. Its evaluation within the tetragonal, trigonal and cubic phases present was performed by a whole powder pattern decomposition procedure according to Pawley. Going beyond previous work, the applied refinements directly include the influence of elastic anisotropy on the residual stress results. Starting from the single‐crystal elastic coefficients, the X‐ray elastic constants according to the Voigt and Reuss models were calculated. Finally, the Neerfeld–Hill model as a generalization was implemented to introduce the hkl‐specific X‐ray elastic constants for calculating the residual stress magnitude within the least‐squares minimization routine. It was possible to resolve the residual stress state in stacked layers of different chemical and phase composition and to reproduce the results obtained by the classical χ‐ and ω‐inclination sin2Ψ techniques.

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Residual stress gradients in α-Al2O3 hard coatings determined by pencil-beam X-ray nanodiffraction: The influence of blasting media

Cited by 41 publications

References 38 publications

20 Hz synchrotron X-ray diffraction analysis in laser-pulsed WC-Co hard metal reveals oscillatory stresses and reversible composite plastification

20 Hz synchrotron X-ray diffraction analysis in laser-pulsed WC-Co hard metal reveals oscillatory stresses and reversible composite plastification

Complementary High Spatial Resolution Methods in Materials Science and Engineering

Pattern decomposition for residual stress analysis: a generalization taking into consideration elastic anisotropy and extension to higher-symmetry Laue classes

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