ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Repeated impact test is an appropriate way to evaluate coating properties of metal cuttingtools since the cyclic impact loading applied in the test simulates the interrupted cutting process. Forhard CVD coatings with multi-layered structure, the alumina is usually of the lowest toughness andadhesion, and relatively easy to fail in the metal cutting. In the present paper, multilayered coatingsconsisting medium temperature TiCN, Al2O3 and TiN were deposited by chemical vapor deposition(CVD) on the tungsten carbide/cobalt substrate and evaluated using scratch adhesion test and repeatedimpacted test. The phase structure of alumina layers are α or )κ as usually applied in cutting tools, andthe grain size for the α phase one is varied from one micron to four microns. The scratch andindentation test results show that the alumina layer of κ phase is easy to remove under the quasi-staticloading, implying brittleness and low adhesion. The repeated impact test results reveal lower impactresistance for the κ phase alumina, and only adhesive failure can be found, which differs to that of theα phase one. The coarse grained α-Al2O3 layer shows similar adhesion compared to the fine grainedα- Al2O3 in scratch test. The failure mode of the coating with coarse grained α-Al2O3 layer in therepeated impact test is primarily impact wear. No cohesive failure can be found at all load levels, andthis leads to higher impact life than that of the fine grain one. It was shown that the relatively lowadhesion of bottom TiCN layer may not affect the impact resistance
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/57/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.373-374.113.pdf
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