Mechanical Response of Porous and Dense NiTi-TiC Composites
- PDF / 91,075 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 89 Downloads / 231 Views
Y6.6.1
Mechanical Response of Porous and Dense NiTi-TiC Composites Douglas E. Burkes1,2, Guglielmo Gottoli1,2, John J. Moore1,2 and Reed A. Ayers2 1 Metallurgical and Materials Engineering Department, Colorado School of Mines Golden, CO 80401, U.S.A. 2 Center for Commercial Applications of Combustion in Space, Colorado School of Mines Golden, CO 80401, U.S.A. ABSTRACT The Center for Commercial Applications of Combustion in Space (CCACS) at the Colorado School of Mines is currently using combustion synthesis to produce several advanced materials. These materials include ceramic, intermetallic, and metal-matrix composites in both porous and dense form. Currently, NiTi – TiC intermetallic ceramic composites are under investigation for use as a bone replacement material. The NiTi intermetallic has the potential to provide a surface that is capable of readily producing an oxide layer for corrosion resistance. The TiC ceramic has the potential to increase the hardness and wear resistance of the bulk material that can improve the performance lifetime of the implant. Processing parameters are critical to the production of the NiTi – TiC composite and will be discussed. These parameters can lead to the formation of substoichiometric TiC and nickel rich NiTi that changes the overall mechanical and material properties. In addition, the size of the TiC particles present within the bulk product varies with porosity. Both porous and dense samples have been mechanically analyzed employing micro-indentation techniques as well as compression tests in an attempt to characterize the mechanical response of these composites. The effects of the TiC particles, the formation of Ni3Ti intermetallic and the effects of porosity on the overall mechanical and material properties will be discussed. INTRODUCTION Nickel-titanium (NiTi) alloys have emerged as promising candidates for internal and external biomedical devices. The high susceptibility of NiTi alloys to grow a natural or controlled oxide surface layer provides the materials with an important biocompatible property. Specifically, NiTi alloys have shown promise as bone replacement structures, bone fracture fixation plates and nails due to the materials ability to withstand deformation and forces imposed by the surrounding tissue which is similar to the properties of that surrounding tissue. Both porous and dense materials are of interest when applying these alloys to the aforementioned applications. The mechanical and material properties of porous and dense nickel-titanium titaniumcarbide (NiTi – TiC) composites produced using a propagating mode [1] combustion synthesis reaction (SHS) are presented within this article. NiTi – TiC composites can be produced utilizing this processing technique by mixing elemental nickel, titanium and carbon in desired stoichiometric ratios, applying a short energy pulse to the reactant mixture and allowing the combustion wave to self-propagate via an exothermic chemical reaction, consuming the initial reactants and converting them to the desired final pro
Data Loading...
