| AVS 65th International Symposium & Exhibition | |
| Advanced Surface Engineering Division | Tuesday Sessions |
| Session SE-TuA |
| Session: | Wear, Oxidation and Corrosion Protective Coatings |
| Presenter: | Aljaž Drnovšek, Montanuniversität Leoben, Austria |
| Authors: | A. Drnovšek, Montanuniversität Leoben, Austria M. Rebelo de Figueiredo, Montanuniversität Leoben, Austria A. Xia, Montanuniversität Leoben, Austria S. Kolozsvári, Plansee Composite Materials GmbH, Germany H. Vo, Univeristy of California Berkeley P. Hosemann, Univeristy of California Berkeley R. Franz, Montanuniversität Leoben, Austria |
| Correspondent: | Click to Email |
One of the most common methods used to characterize the mechanical properties of hard coating materials is nanoindentation. The further development of nanoindentation in recent years led to new ex-situ and in-situ systems that are capable of measuring mechanical properties such as hardness, elastic modulus and fracture toughness at elevated temperatures. In addition, new measuring procedures such as nano-dynamic mechanical analysis (n-DMA) enable measuring the hardness and elastic modulus at a continuous rate through the entire penetration depth at reduced thermal drift sensibility. This approach yields faster measurements at high temperatures which is beneficial in terms of tip degradation and generally renders the obtained results more reliable. With these new experimental possibilities, the mechanical properties of hard coatings synthesized by physical vapor deposition techniques can now be characterized close to the service temperatures that can reach up to 1000 °C.
In the current work, we tested two magnetron sputtered coatings that are widely used in industrial cutting applications, namely CrAlN and CrAlSiN. The latter is a further development of CrAlN coatings where the columnar growth is interrupted due to the addition of Si resulting in a nanocomposite composed of crystalline CrAl(Si)N grains and an amorphous SiNx grain boundary phase. In particular in the case of CrAlSiN hard coatings, studies analyzing the mechanical properties at high temperature are scarce. High temperature nanoindentation measurements on both coatings were performed up to 700 °C in steps of 100 °C. The room temperature hardness values of 30 GPa (CrAlN) and 36 GPa (CrAlSiN) reduced by approximately 2 GPa per temperature step up to 500 °C. Above this temperature, the hardness of CrAlN continued to decrease while the hardness of CrAlSiN remained largely unchanged. In addition, high temperature tribological tests were conducted in air and inert atmosphere in the same temperature range in order to link the friction and wear behavior to the obtained mechanical properties. This data set is intended to serve as a first step towards a more comprehensive understanding of the high temperature mechanical and tribological properties of hard coatings which is vital for their further development and improvement.