Fabrication of Titanium / Biodegradable-Polymer FGM for Medical Application

2009 ◽  
Vol 631-632 ◽  
pp. 199-204 ◽  
Author(s):  
Yoshimi Watanabe ◽  
Yoshimi Iwasa ◽  
Hisashi Sato ◽  
Akira Teramoto ◽  
Koji Abe
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Medical Application ◽  
Hot Water ◽  
Porous Ti ◽  
Ti Alloys ◽  
Plasma Sintering ◽  
Biodegradable Poly ◽  
Spark Plasma

Ti and Ti alloys are widely used as metallic implants, because of their good mechanical properties and nontoxic behavior. However, they have problems as the implant-materials, namely, high Young’s modulus comparing that of bone and low bonding ability with bone. There is a need to develop the Ti and Ti alloys with lower Young’s modulus and good bonding ability. In previous study, Ti composite containing biodegradable poly-L-lactic-acid (PLLA) fiber has been fabricated to improve these problems. However, this composite has low strength because of the imperfect sintering of Ti matrix. To improve its strength, sintering of Ti matrix should be completed. In this study, Ti-NaCl composite material was fabricated by spark plasma sintering (SPS) method using powder mixture of Ti and NaCl to complete the sintering of Ti matrix. To obtain porous Ti samples, Ti-NaCl composite were put into hot water of 100 oC. The porous Ti was dipped into PLLA melt in order to introduce PLLA into the pores of porous Ti. Finally, Ti-PLLA composite was obtained, and PLLA plays a role as reinforcement of Ti matrix. It was found that the Ti-PLLA composite has gradient structure and mechanical properties.

Densification, Microstructure, and Behavior of Hydroxyapatite Ceramics Sintered by Using Spark Plasma Sintering

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Shufeng Li ◽  
Hiroshi Izui ◽  
Michiharu Okano
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Young’S Modulus ◽  
Spark Plasma Sintering ◽  
Young's Modulus ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Temperature And Pressure

This paper discusses the dependence of the mechanical properties and microstructure of sintered hydroxyapatite (HA) on the sintering temperature and pressure. A set of specimens was prepared from as-received HA powder and sintered by using a spark plasma sintering (SPS) process. The sintering pressures were set at 22.3MPa, 44.6MPa, and 66.9MPa, and sintering was performed in the temperature range from 800°Cto1000°C at each pressure. Mechanisms underlying the interrelated temperature-mechanical and pressure-mechanical properties of dense HA were investigated. The effects of temperature and pressure on the flexural strength, Young’s modulus, fracture toughness, relative density, activation energy, phase stability, and microstructure were assessed. The relative density and grain size increased with an increase in the temperature. The flexural strength and Young’s modulus increased with an increase in the temperature, giving maximum values of 131.5MPa and 75.6GPa, respectively, at a critical temperature of 950°C and 44.6MPa, and the fracture toughness was 1.4MPam1∕2 at 1000°C at 44.6MPa. Increasing the sintering pressure led to acceleration of the densification of HA.

scholarly journals First principles computation of composition dependent elastic constants of omega in titanium alloys: implications on mechanical behavior

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Salloom ◽  
S. A. Mantri ◽  
R. Banerjee ◽  
S. G. Srinivasan
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
First Principles ◽  
Young's Modulus ◽  
Group Vi ◽  
Group V ◽  
Β Phase ◽  
Ti Alloys ◽  
Ω Phase ◽  
Stabilizer Concentration

AbstractFor decades the poor mechanical properties of Ti alloys were attributed to the intrinsic brittleness of the hexagonal ω-phase that has fewer than 5-independent slip systems. We contradict this conventional wisdom by coupling first-principles and cluster expansion calculations with experiments. We show that the elastic properties of the ω-phase can be systematically varied as a function of its composition to enhance both the ductility and strength of the Ti-alloy. Studies with five prototypical β-stabilizer solutes (Nb, Ta, V, Mo, and W) show that increasing β-stabilizer concentration destabilizes the ω-phase, in agreement with experiments. The Young’s modulus of ω-phase also decreased at larger concentration of β-stabilizers. Within the region of ω-phase stability, addition of Nb, Ta, and V (Group-V elements) decreased Young’s modulus more steeply compared to Mo and W (Group-VI elements) additions. The higher values of Young’s modulus of Ti–W and Ti–Mo binaries is related to the stronger stabilization of ω-phase due to the higher number of valence electrons. Density of states (DOS) calculations also revealed a stronger covalent bonding in the ω-phase compared to a metallic bonding in β-phase, and indicate that alloying is a promising route to enhance the ω-phase’s ductility. Overall, the mechanical properties of ω-phase predicted by our calculations agree well with the available experiments. Importantly, our study reveals that ω precipitates are not intrinsically embrittling and detrimental, and that we can create Ti-alloys with both good ductility and strength by tailoring ω precipitates' composition instead of completely eliminating them.

scholarly journals Formation and Properties of the Ta-Y2O3, Ta-ZrO2, and Ta-TaC Nanocomposites

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
J. Jakubowicz ◽  
M. Sopata ◽  
G. Adamek ◽  
P. Siwak ◽  
T. Kachlicki
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Ceramic Composites ◽  
Ceramic Phase ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Bulk Nanocrystalline

The nanocrystalline tantalum-ceramic composites were made using mechanical alloying followed by pulse plasma sintering (PPS). The tantalum acts as a matrix, to which the ceramic reinforced phase in the concentration of 5, 10, 20, and 40 wt.% was introduced. Oxides (Y2O3 and ZrO2) and carbides (TaC) were used as the ceramic phase. The mechanical alloying results in the formation of nanocrystalline grains. The subsequent hot pressing in the mode of PPS results in the consolidation of powders and formation of bulk nanocomposites. All the bulk composites have the average grain size from 40 nm to 100 nm, whereas, for comparison, the bulk nanocrystalline pure tantalum has the average grain size of approximately 170 nm. The ceramic phase refines the grain size in the Ta nanocomposites. The mechanical properties were studied using the nanoindentation tests. The nanocomposites exhibit uniform load-displacement curves indicating good integrity and homogeneity of the samples. Out of the investigated components, the Ta-10 wt.% TaC one has the highest hardness and a very high Young’s modulus (1398 HV and 336 GPa, resp.). For the Ta-oxide composites, Ta-20 wt.% Y2O3 has the highest mechanical properties (1165 HV hardness and 231 GPa Young’s modulus).

scholarly journals Sintering of Ti-based biomedical alloys with increased oxygen content from elemental powders

2020 ◽  
Vol 321 ◽  
pp. 05010
Author(s):  
J. Stráský ◽  
J. Kozlík ◽  
K. Bartha ◽  
D. Preisler ◽  
T. Chráska
Keyword(s):  
Mechanical Properties ◽  
Oxygen Content ◽  
High Strength ◽  
Simple Approach ◽  
Fine Tuning ◽  
Powder Metallurgy Method ◽  
Ti Alloys ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Low Modulus

Revived interest for beta Ti alloys with increased oxygen content is motivated by the prospect of achieving material with low modulus and high strength simultaneously. Fine tuning of amount of oxygen and beta stabilizing elements is critical for achieving good mechanical properties. This study shows that powder metallurgy method of spark plasma sintering is capable of producing Ti-Nb-Zr-O alloys from elemental powders. This simple approach allows for quick sampling and production of several alloys with various chemical composition. Elemental powders were mixed with appropriate amount of titanium dioxide to achieve Ti-29Nb-7Zr-0.7O alloy. Sintering was performed at 1400 - 1500 °C for 15 – 30 minutes.

Radiation and thermal effects on polymeric immobilization devices used in patients submitted to radiotherapy

2011 ◽  
Vol 11 (2) ◽  
pp. 101-106
Author(s):  
C. Pereira-Loch ◽  
R. Benavides ◽  
M. Fogliato S. Lima ◽  
B.M. Huerta
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Young’S Modulus ◽  
Thermal Effects ◽  
Young's Modulus ◽  
Thermal Conditions ◽  
Joint Effect ◽  
Hot Water ◽  
Slight Variation ◽  
The Stability

AbstractImmobilization devices in radiotherapy are made of a soft plastic easy to mould when immersed in hot water. Same item is usually used for 6 patients (according to protocol), but at Hospital Sao Jose (HSJ) they have been showing some deformation during the re-utilization process. The latter is the reason for this research where devices were treated with 6 thermal conditions, 6 irradiation procedures and the joint effect of both treatments. DSC, TGA and WAXD indicated devices are made of polycaprolactone (PCL), but no signs of degradation, except a slight variation in crystalinity; however, mechanical properties by means of Young’s modulus steadily increase its values through number of treatments up to a 20%. Activation energy (Ea) obtained by multi-ramps of TGA-Arrhenius evaluated for the most treated samples (6th treatment) indicates that temperature facilitates degradation while irradiation and joint treatments enhance the stability of PCL, apparently by crosslinking.

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.

scholarly journals Controlling of mechanical property in additive manufactured porous titanium by structural control and alloying for bone substitutes

2020 ◽  
Vol 321 ◽  
pp. 05004
Author(s):  
Masato Ueda ◽  
Masahiko Ikeda
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Young’S Modulus ◽  
Structural Control ◽  
Bone Ingrowth ◽  
Young's Modulus ◽  
Bone Substitutes ◽  
Cross Sectional ◽  
Porous Ti ◽  
Fe Alloys

Mechanical properties of metallic materials can be controlled by not only alloy design but also constructing appropriate structure. A porous material with adequate pore structure showing appropriate mechanical properties has long been sought as the ideal bone substitute, because it exhibits low Young’s modulus and bone ingrowth. Additive manufacturing (AM) can produce metallic tailor-made products such as artificial bone, several joints etc. The purpose of this work was to control the mechanical property of porous Ti by controlling the porous structure. In addition, the characteristics of Ti-Zr-Fe alloys were also investigated as the materials for the AM. First, porous polylactic acid with rhombicuboctahedron-derived structure was prepared by a 3D printer to determine appropriated structure for bone substitutes. The compressive strength and Young’s modulus was strongly influenced by the minimum cross-sectional area fraction perpendicular to the loading direction. Then the porous Ti with similar structures were prepared by a laser AM. The strength and Young’s modulus were extremely low compared with the expected ones. Then Ti-xmass%Zr-1mass%Fe alloys (x=0, 5, 10) were prepared as the materials for the AM. Vickers hardness increased almost linearly with Zr content by solution hardening. Ideal bone substitutes would be produced by such structural design and alloying.

scholarly journals SPS sintering of nitride ceramics

Mechanik ◽  
2019 ◽  
Vol 92 (5-6) ◽  
pp. 366-370
Author(s):  
Piotr Wyżga ◽  
Piotr Klimczyk ◽  
Jolanta Cyboroń ◽  
Paweł Figiel
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
Initial Mixture ◽  
Fast Method ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Field Assisted Sintering

Due to the unique properties of ceramics materials based on nitride, it could be used in the broadly understood technique. However, obtaining silicon nitride materials requires it to use the advanced methods of manufacturing, mostly because this material is difficult to sinter. Dense ceramic sinters were obtained from the system Si3N4-Al2O3-Y2O3 by applied pulsed current – SPS/FAST method (spark plasma sintering/field assisted sintering technique). The sintering parameters of the initial mixture were optimized to obtain the highest possible sinter properties, such as: density, Young’s modulus, hardness and fracture toughness. In the presented work the influence of pressure and pulse current, used in the SPS/FAST method, on sinterability and on selected physical and mechanical properties of the obtained materials was analyzed. The purpose of introducing the Al2O3 and Y2O3 additions to the Si3N4 matrix was to activate the hard-to-sinter silicon nitride powder and consequently to achieve a high density of the sintered samples. The best properties were characterized by sinter obtained in 1700°C and under pressure 63 MPa; the holding time at sintering temperature was 15 min. The density of the obtained sample has reached 98% theoretical value, and the other parameters were: Young’s modulus – 298 GPa, Vickers hardness – 17,7 GPa, fracture toughness – 6 MPa∙m1/2.

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