Damage Characteristics and Evolution of Multilayer TiN/Ti Coatings under Cyclic Impact with Different Temperatures

The work aims to explore the effect of temperature on the impact wear of ceramic-metal multilayer coatings, to obtain the impact wear characteristics and to reveal the failure mechanism of ceramic metal coatings under the combined action of temperature and cyclic impact. According to these results, it provides a reference for the design and use of multilayer coatings. Firstly, the vertical impact tests of ceramic-metal multilayer coatings at different temperatures (35 ℃, 200 ℃, 350 ℃, 500 ℃) were carried out by using a single particle cyclic impact equipment with adjustable temperature unit. Then the morphology and microstructure of the impact crater were observed by white light interferometer, optical microscope and scanning electron microscope. Finally, the damage mechanism of the coating was analyzed by combining the nano-hardness and elastic modulus of the coating at different temperatures. It has been found that at relatively low temperature (35 ℃, 200 ℃), the circular crack is the main damage form of the coating, and the impact pit depth of the coating increases slowly after reaching stability. At higher temperatures (350 ℃ and 500 ℃), the damage characteristics of the coating changed from circular cracks to radial cracks and spalling, and the depth of impact pits increased rapidly. When the temperature increases from 35 ℃ to 500 ℃, the nano-hardness decreased from 31.22 GPa to 11.18 GPa, and the H³/E² decreased from 38.38×10^‒2 GPa to 2.85×10^‒2 GPa. The peak impact force and energy absorption rate of the coating increase from 167.8 N, 72.44% to 184.6 N, 82.37%, respectively, resulting in the aggravation of the damage degree of the coating. And the impact pit depth of the coating increases from 4.74 µm to 11.58 µm. The impact damage characteristics and properties of ceramic-metal multilayer coatings are affected by temperature. With the increase of temperature, the nano-hardness and toughness of ceramic-metal multilayer coatings decrease, the peak impact force and energy absorption rate increase. And the impact damage depth of the coating will be increased at the same impact cycles.