Formation and wear mechanism of nickel titanium intermetallics during heat treatment of nickel coating on Ti-6Al-4V substrate |
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Authors: | Majid Abdoos Mohsen Adabi |
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Affiliation: | 1. School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran;2. McMaster Manufacturing Research Institute (MMRI), Department of Mechanical Engineering, McMaster University, Hamilton, Canada;3. Young Researchers and Elite Club, Roudehen Branch, Islamic Azad University, Roudehen, Iran |
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Abstract: | In the present work, inter-diffusion of nickel and titanium and formation of Ni-Ti intermetallic compounds on Ti-6Al-4V substrate have been studied. Initially, nickel was electrodeposited on the alloy using a modified Watts bath solution at a current density of 2 A dm?2 for 1?h. The coated specimens were then heat treated for different durations at 750, 800 and 850 °C under argon atmosphere. The effects of temperature and time on the characteristics, hardness and wear resistance of intermetallic phases were investigated. The results showed that a multilayer structure was formed after heat treatment, an outer layer of residual nickel, an area of intermetallic layers with different compositions followed by a solid solution of Ni-Ti. It was also observed that an increase in time or temperature at first led to the formation of thicker intermetallic layers; however, after passing a critical point, the intermetallic layers seem to dissolve into the substrate. Furthermore, the wear rates of the diffusion treated samples were four times lower compared to Ti-6Al-4V alloy when sliding against AISI 52100 hardened steel. |
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Keywords: | Ti-6Al-4V alloy diffusion treatment electrodeposition intermetallic formation wear resistance |
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