Insitu laser deposition of NiTi intermetallics forcorrosion improvement of Ti-6Al-4V alloy
(1. Department of Chemical,Metallurgical and Materials Engineering,
Tshwane University of Technology,Pretoria 0001, South Africa;
2. Council for Scientific and Industrial Research, National Laser Centre, Pretoria 0001, South Africa)
Tshwane University of Technology,Pretoria 0001, South Africa;
2. Council for Scientific and Industrial Research, National Laser Centre, Pretoria 0001, South Africa)
Abstract: NiTi intermetallic coatings were fabricated on the surface of Ti-6Al-4V alloyby melting Ni and Ti powders using laser metal deposition (LMD) process. The effects of NiTi reinforcement content on the microstructure, hardness and corrosion properties of the coatings were examined.The results show that the deposited coatings are characterized by NiTi, NiTi2 and NiTi3 intermetallic phases. An appreciable increase in corrosion resistance is obtainedfor all the coatings, and Ti55Ni45 coating shows the highest corrosion resistance; while coatings Ti50Ni50 and Ti45Ni55 follow in that succession. The reinforcement materials are proven to be corrosion resistant in the tested environment, and the effect of Ti is more dominant.
Key words: Ti-6Al-4V alloy; NiTi intermetallic; laser metal deposition; corrosion behaviour