English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Residual stresses and thermal fatigue in CrN hard coatings characterized by high-temperature synchrotron X-ray diffraction

MPS-Authors
There are no MPG-Authors available
Locator
There are no locators available
Fulltext (public)
There are no public fulltexts available
Supplementary Material (public)
There is no public supplementary material available
Citation

Kirchlechner, C., Martinschitz, K. J., Daniel, R., Klaus, M., Genzel, C., Mitterer, C., et al. (2010). Residual stresses and thermal fatigue in CrN hard coatings characterized by high-temperature synchrotron X-ray diffraction. Thin Solid Films, 518(8), 2090-2096. doi:10.1016/j.tsf.2009.08.011.


Cite as: http://hdl.handle.net/11858/00-001M-0000-001A-239B-7
Abstract
The aim of this work is to analyze thermal fatigue in hard coatings/substrate composites (i) during slow heating and cooling and (ii) after local cyclic thermal laser pulse experiments. As a model system, CrN coatings with a thickness of 3 μm deposited on steel, hard metal and Si(100) substrates using reactive magnetron sputtering at a temperature of 350 °C are used. The coatings are at first characterized by means of in-situ high-temperature X-ray diffraction (XRD) using a commercially available temperature attachment and by applying heating and cooling rates of less than 0.3 °C/s. The treatment results in the expected reduction of intrinsic stresses which are independent of substrate material but strongly influenced by substrate roughness. To simulate local thermal fatigue, selected coating/substrate composites are thermally cycled using a laser beam of 6 mm in diameter in a temperature range of 50–850 °C applying up to 104 cycles and using heating and cooling rates of about 103 °C/s. Subsequently, laser cycled samples are analyzed using synchrotron XRD, scanning electron microscopy and focused ion beam technique. Laser pulses cause a reduction of compressive stresses in the coatings and a development of tensile stresses in the substrates accompanied by formation of cracks and ripples. The results show that the changes of the local macro- and micro-strains/stresses in the coatings and in the underlying substrates are strongly interlinked. The stress relaxation in the coatings is caused by recovery effects, by micro-cracks formed in the tensely-stressed coating and by plastic deformation of the metallic substrates.