1. Microstructure and Corrosion Resistance of Laser-Welded Crossed Nitinol Wires
- Author
-
Runhua Yao, Jun Zhou, Peng Dong, Yan Zheng, He Xiuli, Zhifeng Yan, and Wenxian Wang
- Subjects
010302 applied physics ,Austenite ,Heat-affected zone ,corrosion ,Materials science ,nickel–titanium ,laser welding ,intermetallics ,Precipitation (chemistry) ,Laser beam welding ,02 engineering and technology ,Welding ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,Article ,law.invention ,Corrosion ,law ,Nickel titanium ,0103 physical sciences ,General Materials Science ,Composite material ,0210 nano-technology - Abstract
Laser welding has been considered to be one of the most promising joining processes for Nitinol medical device manufacturing. Presently, there is still a limited understanding about how laser welding affects the microstructure and the resultant corrosion behaviors. This work aimed to reveal the microstructural factors that influence the corrosion resistance of laser-welded crossed Nitinol joints. The microstructures within various zones of the joints were characterized by using transmission electron microscopy (TEM), and the corrosion behaviors of the joints in 0.9% NaCl and Hank’s solutions were studied. The base metal exhibits a single austenite (B2) phase and the highest corrosion resistance. The phase constituent of the fusion zone is the coexistence of the B2 matrix and some precipitates (T2Ni, TiNi3, and Ti3Ni4 particles), resulting in a slight decrease in corrosion resistance. The heat affected zone (HAZ) shows the austenite matrix but with the precipitation of R-phase, which considerably reduces the corrosion potential, making it the weakest zone.
- Published
- 2018