Simplified fractal FEA model for the estimation of the Young’s modulus of Ti foams obtained by powder metallurgy

2015 ◽  
Vol 83 ◽  
pp. 276-283 ◽  
Author(s):  
L. Pérez ◽  
S. Lascano ◽  
C. Aguilar ◽  
D. Domancic ◽  
I. Alfonso
Keyword(s):  
Powder Metallurgy ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Fea Model

Fabrication and Testing of Planar Stent Mesh Designs Using Carbon-Infiltrated Carbon Nanotubes

2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Kristopher Jones ◽  
Brian D. Jensen ◽  
Anton Bowden
Keyword(s):  
Carbon Nanotubes ◽  
Young’S Modulus ◽  
Fracture Strain ◽  
Young's Modulus ◽  
Chemical Vapor ◽  
Pyrolytic Carbon ◽  
Compression Tests ◽  
Element Analysis ◽  
Percent Elongation ◽  
Fea Model

This paper explores and demonstrates the potential of using pyrolytic carbon as a material for coronary stents. Stents are commonly fabricated from metal, which has worse biocompatibilty than many polymers and ceramics. Pyrolytic carbon, a ceramic, is currently used in medical implant devices due to its preferable biocompatibility properties. Micropatterned pyrolytic carbon implants can be created by growing carbon nanotubes (CNTs), and then filling the space between with amorphous carbon via chemical vapor deposition (CVD). We prepared multiple samples of two different stent-like flexible mesh designs and smaller cubic structures out of carbon-infiltrated carbon nanotubes (CI-CNT). Tension loads were applied to expand the mesh samples and we recorded the forces at brittle failure. The cubic structures were used for separate compression tests. These data were then used in conjunction with a nonlinear finite element analysis (FEA) model of the stent geometry to determine Young's modulus and maximum fracture strain in tension and compression for each sample. Additionally, images were recorded of the mesh samples before, during, and at failure. These images were used to measure an overall percent elongation for each sample. The highest fracture strain observed was 1.4% and Young's modulus values confirmed that the material was similar to that used in previous carbon-infiltrated carbon nanotube work. The average percent elongation was 86% with a maximum of 145%. This exceeds a typical target of 66%. The material properties found from compression testing show less stiffness than the mesh samples; however, specimen evaluation reveals poorly infiltrated samples.

Fabrication of Porous NiTi Alloy Using Organic Binders

2018 ◽  
pp. 38-62
Author(s):  
Neeraj Sharma ◽  
Kamal Kumar
Keyword(s):  
Powder Metallurgy ◽  
Young’S Modulus ◽  
Process Parameters ◽  
Mechanical Treatment ◽  
Young's Modulus ◽  
Niti Alloy ◽  
Compaction Pressure ◽  
Porous Niti ◽  
Organic Particles ◽  
Bio Compatibility

Nitinol has growing applications in aerospace industries, MEMS, and bio-medical industries due to its unique properties of pseudo-elasticity, bio-compatibility, and shape-memory effect. Behaviour of NiTi alloy can be changed by altering the composition, modifying the porosity, and applying external thermal and mechanical treatment. In this chapter, porous NiTi alloy with powder metallurgy is fabricated by varying the composition of polypropylene as an organic binder from 0% to 15%, and Young's modulus and porosity of porous alloy has been evaluated. The effect of process parameters—compaction pressure, sintering temperature, and sintering time—are evaluated using Taguchi L16 orthogonal array. These particles initially act as a binder but with the increase of temperature, the organic particles evaporate and create pores. With the increase of organic particle percentage, the porosity increases while Young's modulus decreases. SEM was used to characterize the fabricated porous NiTi alloy.

The Effect of Pressure and Pore-Forming Agent on the Mechanical Properties of Porous Titanium

2011 ◽  
Vol 217-218 ◽  
pp. 1191-1196
Author(s):  
Peng Zhang ◽  
Yuan Chen Qi ◽  
Wei Li
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Cortical Bone ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Porous Titanium ◽  
Human Bone ◽  
Cold Isostatic Press ◽  
Effect Of Pressure ◽  
Porous Ti

Porous titanium compacts were fabricated by powder metallurgy using cold isostatic press with and without pore forming agents. Their microstructure and mechanical properties were investigated in this study. These alloy powders were sintered under 1300°C in vacuum of 10-3 Pa for 2h, followed by furnace cooling. Young’s modulus of sintered Ti could equal that of human’s dense bones. It was found that the strength of porous Ti enhanced by increasing the pressure or decreasing the amounts of pore forming agents. We prepared a porous pure Ti with 30wt.% NH4HCO3 as pore forming agents whose modulus was near to the human cortical bone, as compared in the range from 10 to 30GPa of Young’s modulus for human bone.

Detection for Spring Constant of Microcantilevers in Atomic Force Microscopy Based on Frequency Measurements

2009 ◽  
Vol 60-61 ◽  
pp. 49-52
Author(s):  
Fei Wang ◽  
Xue Zeng Zhao
Keyword(s):  
Atomic Force Microscopy ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Spring Constant ◽  
Force Microscopy ◽  
Frequency Measurements ◽  
Fea Model ◽  
Atomic Force ◽  
Vibration Model ◽  
Micro Cantilever

Micro cantilevers in atomic force microscopy are important force sensors in nano research, and the spring constant is one of the most important parameters of the cantilevers. Normal testing methods are not suitable for the spring constant detecting of micro cantilevers according to the strict scale of the cantilevers, and new methods are needed to the study of micro cantilevers. A method for detecting of spring constant of micro cantilevers based on combining the numerical simulation and frequency measurements is presented in this paper. The new method involves four steps, the first step is developing the vibration model of the micro cantilever studied immersed in air and determine the fluid parameters in the model during dynamic tests in atomic force microscopy presented in this paper; the second step is analyzing the vibration behavior of the corresponding cantilevers with the same geometry but different young’s modulus. The third step is measuring the natural frequencies of the micro cantilevers and comparing the experimental results with the numerical results to determine the young’s modulus of the cantilever. The last step is conducting the young’s modulus to the cantilever FEA model for determination of its spring constant. Experiments on a NSC cantilever have been done to validate the method presented in this paper.

scholarly journals Porous Titanium for Biomedical Applications: Evaluation of the Conventional Powder Metallurgy Frontier and Space-Holder Technique

2019 ◽  
Vol 9 (5) ◽  
pp. 982 ◽  
Author(s):  
Sheila Lascano ◽  
Cristina Arévalo ◽  
Isabel Montealegre-Melendez ◽  
Sergio Muñoz ◽  
José Rodriguez-Ortiz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Young’S Modulus ◽  
Biomedical Applications ◽  
Mechanical Response ◽  
Young's Modulus ◽  
Pure Titanium ◽  
Porous Titanium ◽  
Space Holder ◽  
Industrial Implementation

Titanium and its alloys are reference materials in biomedical applications because of their desirable properties. However, one of the most important concerns in long-term prostheses is bone resorption as a result of the stress-shielding phenomena. Development of porous titanium for implants with a low Young’s modulus has accomplished increasing scientific and technological attention. The aim of this study is to evaluate the viability, industrial implementation and potential technology transfer of different powder-metallurgy techniques to obtain porous titanium with stiffness values similar to that exhibited by cortical bone. Porous samples of commercial pure titanium grade-4 were obtained by following both conventional powder metallurgy (PM) and space-holder technique. The conventional PM frontier (Loose-Sintering) was evaluated. Additionally, the technical feasibility of two different space holders (NH4HCO3 and NaCl) was investigated. The microstructural and mechanical properties were assessed. Furthermore, the mechanical properties of titanium porous structures with porosities of 40% were studied by Finite Element Method (FEM) and compared with the experimental results. Some important findings are: (i) the optimal parameters for processing routes used to obtain low Young’s modulus values, retaining suitable mechanical strength; (ii) better mechanical response was obtained by using NH4HCO3 as space holder; and (iii) Ti matrix hardening when the interconnected porosity was 36–45% of total porosity. Finally, the advantages and limitations of the PM techniques employed, towards an industrial implementation, were discussed.

Formation of Porous Structure of the Metallic Materials Used on Bone Implants

2011 ◽  
Vol 183 ◽  
pp. 155-162 ◽  
Author(s):  
Tomasz Seramak ◽  
Waldemar Serbiński ◽  
Andrzej Zieliński
Keyword(s):  
Corrosion Resistance ◽  
Powder Metallurgy ◽  
Porous Material ◽  
Porous Structure ◽  
Porous Materials ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Ti Alloy ◽  
Bone Implants ◽  
Human Bones

Research on improvement of structure and fabrication methods of the bone implants are carried out for many years. Research are aimed to shape the structures, that will have a Young's modulus value similar to the value of the human bones Young's modulus. Depending on the porosity, Young’s moduli can even be tailored to match the modulus of bone closer than solid metals can, thus reducing the problems associated with stress shielding of a human bones. The designed structure should also be characterized by a high abrasion and corrosion resistance to and allow bone ingrowth in the implant material to make the best bone-implant fixation. For this purpose, implants should have a porous structure with an appropriate pore size and with open-cell porosity. Material for bone implants must also have a high biocompatibility and bioactivity. Following these requirements, the metallic porous materials appear to be the most suitable material for bone implants. In this paper a various methods of a porous materials fabrication for bone implants are listed. It was shown that titanium and its alloys (e.g. Ti6Al4V or Ti13Nb13Zr) are widely used as biomaterials for implants. Research in order to increase their wear and corrosion resistance and to improve their biocompatibility and bioactivity are still carried out. One of the most effective methods of manufacturing the porous materials is a powder metallurgy (PM). In this paper the results of research under shaping the structure of the porous titanium alloy Ti13Nb13Zr are also presented. As a manufacturing method of the porous material from the investigated and mentioned above Ti alloy, the powder metallurgy (PM) was choosen - with and without the use of a space holders. Method of fabrication a spherical powder from the aforementioned Ti alloy and results of its morphology research are discussed. The applied powder compaction method (with use and without use of space holders) and the influence of a sintering process on the final microstructure morphology of porous material obtained from Ti13Nb13Zr alloy are also presented and discussed.

Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Milling Time ◽  
Young's Modulus ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

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