Structure, properties and wear performance of nano-multilayered TiAlCrSiYN/TiAlCrN coatings during machining of Ni-based aerospace superalloys

摘要

New nano-multilayered TiAlCrSiYN/TiAlCrN coatings have been developed with various ratios of Ti/Al/Cr within Si. +. Y containing nano-layers.The layered nanostructure of the coatings has been studied by STEM-HAADF mode and the nano-metric composition obtained by in-situ EDS. Micro-mechanical characteristics were investigated using a Micro Materials NanoTest System. Thermogravimetric-Differential Thermal Analysis (TG-DTA) was used within a temperature range of 25-1200~°C for oxidation resistance evaluation.The wear performance of nano-multilayered TiAlCrSiYN/TiAlCrN coatings during machining of direct aged Inconel (DA) 718 and powder metallurgical ME 16 Ni-based superalloys has been investigated. The kinetic coefficient of friction under metal cutting conditions of Inconel was measured. The temperature range was 25-1000~°C.It was shown that the composition of the nano-multilayered coatings and their characteristics have to be tuned for specific applications. A nano-multilayered coating with increased amount of Al (60. at.%) in Si. +. Y containing nano-layers that has strong oxidation resistance and a higher range of micro-mechanical properties related to crack propagation under scratch conditions behaves better during machining of Inconel DA 718 alloy. For machining of the more high temperature strong and thermally resistant ME 16 superalloy, a nano-multilayered coating with less Al (55. at.%) in Si. +. Y containing nano-layers that combines improved oxidation resistance with higher hardness and other beneficial micro-mechanical properties associated with resistance to plastic deformation performs best.