Regensburg 2013 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
MM: Fachverband Metall- und Materialphysik
MM 53: Topical Session: Fundamentals of Fracture - Novel Experimental Techniques II
MM 53.2: Talk
Thursday, March 14, 2013, 12:00–12:15, H4
Cracking in 'nanocomposite' CrAlN/Si3N4 hard coatings — Shiyu Liu1, Jeff Wheeler2, Philip R. Howie1, Xiangting Zeng3, Johann Michler2, and •William J. Clegg1 — 1Gordon Laboratory, Department of Materials Science & Metallurgy, Pembroke St, Cambridge CB2 3QZ, UK — 2EMPA, Feuerwekerstrasse 39, CH-3062 Thun, CH — 3Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075
Recent work has shown that the flow behaviour of hard coatings of a very fine-grained CrAlN/Si3N4 is similar to that predicted by expanding cavity type models. However, preliminary observations suggest that the cracking behaviour of these materials is somewhat different to that observed in more conventional CrAlN hard coatings. In this paper, a double cantilever beam method has been developed to study the nature of crack growth in hard coatings. The test method is first described, including a way of correcting for frictional effects between the punch and the sample. The measured values of the crack resistance of SiC and GaAs are compared with those obtained at larger scales. The method is then used to measure the resistance to cracking in different hard CrAlN-based coatings and to study how a crack grows through the coating and the influence of the coating microstructure.