Nano and micro- structural self-organization of implant surface from nitinol, fabricated by laser control SHS
- PDF / 3,118,448 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 100 Downloads / 193 Views
Nano and micro- structural self-organization of implant surface from nitinol, fabricated by laser control SHS Igor V. Shishkovsky1, Yuri G. Morozov2 1 P. N. Lebedev Physics Institute of Russian Academy of Sciences, Samara branch, NovoSadovaja st. 221, Samara 443011, Russia, [email protected] 2 Institute of Structural Macrokinetics and Materials Science (ISMMS), RAS, Chernogolovka, Moscow reg., Russia.
ABSTRACT Topology of the surface micro- and nano- structures induced by the synthesis of NiTi intermetallic phases under Selective Laser Sintering is studied by Scanning Electron Microscopy. According previously developed us method, those data were analysed by image processing software for identification and discussion of common features and peculiarities of the phase and structural transformations. It was shown, that fine substructures have selfordering nature. Geometric similarity of synthesizing structures expects their fractal nature. The dependence between the fractal dimension -D of low-dimensional nanostructures and laser energy input -A was found. The change of the fractal dimension of low dimensional structures clearly correlates with the change of roughness, while the increase of the laser energy input influences the fractal dimension - D in different ways. Shown that particularities of phase structural transformations at the intermetallic synthesis in the Ni-Ti system have been defined an appearance of nano sized and self-ordering substructures of cellular, dendrite or mosaic types. A sharp variation of the D orientation indicates about of change of the phaseformation mechanism. INTRODUCTION Early [1] we showed that the intermetallic NiTi samples of desired shape could be synthesized directly by combining Selective Laser Sintering (SLS) and self-propagating high-temperature synthesis (SHS) methods. Though porous, the obtained samples were durable and compatible with the infiltration by a bioactive preparation in order to enhance the implantation process [2]. The optimal regimes of laser control for the synthesis reaction were determined and compared with results of a pre-alloying nitinol SLS process. The heat separation during exothermal reaction of synthesis is significantly decreasing a laser energy input during SLS+SHS realization in compare with pure SLS. However such combined process is harder control, and phase product composition includes other intermetallic phases. The experience has been gained by studying structural and phase transformations in this complex intermetallic system as well as physical–mechanical and corrosion properties of the final products. The our experimental researches were done to study microstructure, density, water absorption, open porosity, and corrosion behaviour of the 3D samples synthesized by SLS+SHS from NiTi powder mixtures [3]. A vital current need for regenerative surgery is the substitution of cast implant materials by porous 3D matrices for tissue. It generally is known that the topography of a porous surface, compared to that of a smooth one, has an impact on the mo
Data Loading...
