Evolution of the fracture properties of arc evaporated Ti1-xAlxN coatings with increasing Al content
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Authors
Organisational units
External Organisational units
- Ceratizit Austria GmbH
- Christian Doppler Laboratory of Advanced Coated Cutting Tools
Abstract
Although the positive effect of an increasing Al content in Ti1-xAlxN hard coatings within the cubic regime is thoroughly investigated, there is a lack of systematic studies on the fracture properties. Thus within the present work, seven Ti1-xAlxN coatings with increasing Al content from x = 0 up to x = 0.78 were deposited by cathodic arc evaporation. Using scanning electron microscopy and X-ray diffraction, a grain refinement with increasing Al content up to x = 0.65 could be observed, while the coating with the highest Al content of x = 0.78 showed again a coarser grain size. The presence of a single phase face-centered cubic (fcc)-structure up to an Al content of x = 0.49 was confirmed by X-ray diffraction. Ti0.44Al0.56N and Ti0.35Al0.65N exhibited a dual phase fcc- and wurtzitic (w)-structure, where for the latter the w-structure is dominating. A single phase w-structure was observed for the Ti0.22Al0.78N coating. Nano-indentation experiments revealed an increasing hardness with increasing Al content up to x = 0.56 and thus, as long as the fcc-phase is dominating, due to decreasing grain size and increasing compressive stress. For the coatings with dominating and pure w-structure a drop in hardness was observed. Similar to the hardness, the micromechanical bending tests also revealed improving fracture properties with increasing Al content up to x = 0.56 and deteriorating fracture properties when the w-structure becomes dominant.
Details
Original language | English |
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Article number | 128690 |
Number of pages | 6 |
Journal | Surface & coatings technology |
Volume | 444.2022 |
Issue number | 25 August |
DOIs | |
Publication status | Published - 16 Jul 2022 |