陶瓷-金属多层涂层不同温度循环冲击损伤特征与演化规律

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

目的探讨环境温度对陶瓷-金属多层涂层冲击损伤的影响,获得不同温度条件下涂层的冲击损伤特征,揭示陶瓷-金属涂层在温度与循环冲击共同作用下的失效机理,为多层涂层的设计和使用提供参考。方法首先使用可调温度的速度控制型单颗粒循环冲击设备,对陶瓷-金属多层涂层在不同温度(35、200、350、500℃)下进行垂直冲击试验。采用白光干涉仪、光学显微镜和扫描电镜观察冲击坑的形貌和微观结构,结合不同温度时涂层纳米硬度和弹性模量来分析其损伤机理。结果温度较低(35、200℃)时,圆周裂纹是涂层的主要损伤形式,涂层冲击坑深度在达到稳定后增长缓慢;温度较高(350、500℃)时,涂层损伤特征由圆周裂纹向径向裂纹和剥落转化,冲击坑深度的增长速度较快。当温度从35℃提高到500℃时,涂层纳米硬度从31.22 GPa下降到11.18 GPa,H^(3)/E^(2)从38.38×10^(‒2) GPa下降到2.85×10^(‒2) GPa,涂层的峰值冲击力和能量吸收率分别从167.8 N和72.44%增长到184.6 N和82.37%,加剧涂层的损伤,使涂层冲击坑深度从4.74μm增长到11.58μm。结论陶瓷-金属多层涂层的冲击损伤特征和性能受温度影响,温度升高使得涂层的纳米硬度和韧性H^(3)/E^(2)同时降低,循环冲击条件下的峰值冲击力和能量吸收率均增大,相同循环次数时,将增大涂层的冲击损伤深度。

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 H^(3)/E^(2) 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 4.74μm to 11.58μm.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.