Publication Date:
2017-09-23
Description:
Nano-multilayered TiAlN/CrAlN coatings combining advantages of Ti-Al-N and Cr-Al-N are considered to be promising candidates for advanced machining processes. Here, the structure and thermal properties of Ti 1- x Al x N/CrAlN (x = 0.48, 0.58 and 0.66) multilayered coatings as well as referential Ti 1- x Al x N and Cr 0.32 Al 0.68 N monolithic coatings were investigated. Ti 1- x Al x N coatings show a structural transformation from cubic (c) structure for x = 0.48 to mixed cubic and wurtzite (c/w) structure for x = 0.58 and 0.66, and Cr 0.32 Al 0.68 N coating exhibits a single cubic structure. Through a multilayer arrangement with Cr 0.32 Al 0.68 N layers, the Ti 0.52 Al 0.48 N and Ti 0.42 Al 0.58 N layers can be stabilized in their metastable cubic structure, but the Ti 0.34 Al 0.66 N layer still tends to crystallize in the mixed cubic and wurtzite structure. The hardness of Ti 0.52 Al 0.48 N/CrAlN and Ti 0.42 Al 0.58 N/CrAlN coatings is higher than that of corresponding monolithic coatings regardless of as-deposited and annealed states. Especially, after annealing at 800 °C, the Ti 0.52 Al 0.48 N/CrAlN and Ti 0.42 Al 0.58 N/CrAlN coatings reach their peak hardness of ~34.2 and 32.8 GPa due to the spinodal decomposition of Ti 1- x Al x N layers. However, the oxidation resistance of Ti 1- x Al x N/CrAlN coatings is mainly up to the Al content of Ti 1- x Al x N layers, where only the Ti 0.34 Al 0.66 N/CrAlN coating can survive the 10 h exposure to air at 1000 °C. This article is protected by copyright. All rights reserved.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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