title: Lateral gradients of phases, residual stress and hardness in a laser heated Ti0.52Al0.48N coating on hard metal.
abstract: The influence of a local thermal treatment on the properties of Ti-Al-N coatings is not understood. In the present work, a Ti0.52Al0.48N coating on a WC-Co substrate was heated with a diode laser up to 900 °C for 30 s and radially symmetric lateral gradients of phases, residual stress and hardness were characterizedex-situusing position-resolved synchrotron X-ray diffraction, Raman spectroscopy, transmission electron microscopy and nanoindentation. The results reveal (i) a residual stress relaxation at the edge of the irradiated area and (ii) a compressive stress increase of few GPa in the irradiated area center due to the Ti-Al-N decomposition, in particular due to the formation of small wurtzite (w) AlN domains. The coating hardness increased from 35 to 47 GPa towards the center of the heated spot. In the underlying heated substrate, a residual stress change from about - 200 to 500 MPa down to a depth of 6 μm is observed. Complementary,in-situhigh-temperature X-ray diffraction analysis of stresses in a homogeneously heated Ti0.52Al0.48N coating on a WC-Co substrate was performed in the range of 25-1003 °C. Thein-situexperiment revealed the origin of the observed thermally-activated residual stress oscillation across the laser heated spot. Finally, it is demonstrated that the coupling of laser heating to produce lateral thermal gradients and position-resolved experimental techniques opens the possibility to perform fast screening of structure-property relationships in complex materials.
authors.affiliation: Department of Materials Physics, Montanuniversität Leoben, Austria ; Erich Schmid Institute for Materials Science, Austrian Academy of Sciences, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Bartosik
authors.forename: R
authors.initials: R
authors.lastname: Daniel
authors.forename: Z
authors.initials: Z
authors.lastname: Zhang
authors.forename: M
authors.initials: M
authors.lastname: Deluca
authors.forename: W
authors.initials: W
authors.lastname: Ecker
authors.forename: M
authors.initials: M
authors.lastname: Stefenelli
authors.forename: M
authors.initials: M
authors.lastname: Klaus
authors.forename: C
authors.initials: C
authors.lastname: Genzel
authors.forename: C
authors.initials: C
authors.lastname: Mitterer
authors.forename: J
authors.initials: J
authors.lastname: Keckes
keywords: Laser; Phase transformation; Residual stress; Synchrotron; TiAlN; X-ray diffraction