Microstructure and corrosion behavior of laser processed NiTi alloy.
Laser Engineered Net Shaping (LENS™), a commercially available additive manufacturing technology, has been used to fabricate dense equiatomic NiTi alloy components. The primary aim of this work is to study the effect of laser power and scan speed on microstructure, phase constituents, hardness and corrosion behavior of laser processed NiTi alloy. The results showed retention of large amount of high-temperature austenite phase at room temperature due to high cooling rates associated with laser processing. The high amount of austenite in these samples increased the hardness. The grain size and corrosion resistance were found to increase with laser power. The surface energy of NiTi alloy, calculated using contact angles, decreased from 61 mN/m to 56 mN/m with increase in laser energy density from 20 J/mm(2) to 80 J/mm(2). The decrease in surface energy shifted the corrosion potentials to nobler direction and decreased the corrosion current. Under present experimental conditions the laser power found to have strong influence on microstructure, phase constituents and corrosion resistance of NiTi alloy.
Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal, Srinivasnagar P.O. 575 025, India.
Jithin J
JJ
Marattukalam
Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal, Srinivasnagar P.O. 575 025, India.
Amit Kumar
AK
Singh
Bioceramics & Coating Division, CSIR-Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, Kolkata 700 032, India.
Susmit
S
Datta
Bioceramics & Coating Division, CSIR-Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, Kolkata 700 032, India.
Mitun
M
Das
Bioceramics & Coating Division, CSIR-Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, Kolkata 700 032, India. Electronic address: vamsiballa@cgcri.res.in.
Vamsi Krishna
VK
Balla
Department of Mechanical Engineering, National Institute of Technology Karnataka, Surathkal, Srinivasnagar P.O. 575 025 India.
Srikanth
S
Bontha
Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal, Srinivasnagar P.O. 575 025, India. Electronic address: sreeram@nitk.edu.in.
Sreeram K
SK
Kalpathy
D000497:Alloys / Q000737:chemistry* / Q000528:radiation effects*; D003343:Corrosion; D004307:Dose-Response Relationship, Radiation; D007834:Lasers; D009532:Nickel / Q000737:chemistry* / Q000528:radiation effects*; D011829:Radiation Dosage; D013499:Surface Properties / Q000528:radiation effects; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects*
D000497:Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium
Corrosion; Laser engineered net shaping; Laser processing; Microstructure; NiTi alloy