Processing of Ti Scaffolds by Sintering with Different Spacers

2012 ◽  
Vol 727-728 ◽  
pp. 398-403
Author(s):  
Concepción Tojal ◽  
J.J. Candel ◽  
Vicente Amigó ◽  
F. Devesa
Keyword(s):  
Mechanical Properties ◽  
Sodium Chloride ◽  
Porous Materials ◽  
High Vacuum ◽  
Ammonium Bicarbonate ◽  
Low Density ◽  
New Materials ◽  
Space Holder ◽  
Manufacturing Method ◽  
Bone Replacement

Titanium is a material used in biomedicine for osseous implants due to their low density and biocompatibility. Its use in this field is limited by the lack of similarity of their stiffness with the stiffness of bones. In order to reduce this difference, powder metallurgy offers ways to develop porous materials with a reduced stiffness. The main objective of this work is to develop titanium scaffolds by space-holder technique, concretely with using two different spacers: Ammonium bicarbonate and sodium chloride. It has been studied the best way for remove spacer of green compacts, which have been sintered in high vacuum. Materials obtained by using of two spacers, have been analyzed in order to value different results in porosity, microstructural and mechanical properties. The stiffness of new materials was obtained by testing of three points in bending. This research shows that the manufacturing method of porous materials for bone replacement using space holder technique with ammonium bicarbonate or sodium chloride, allows obtained samples with slightly difference in physical, microstructural and mechanical properties.

COMPRESSIVE MECHANICAL PROPERTIES OF POROUS TI-6AL-4V WITH PALM STEARIN BINDER SYSTEM

2015 ◽  
Vol 76 (6) ◽  
Author(s):  
N. H. Mohamad Nor ◽  
J.B Saedon ◽  
N. A. A. Kasim ◽  
M. H. Ismail ◽  
Hazran Husain
Keyword(s):  
Mechanical Properties ◽  
Sodium Chloride ◽  
Volume Fraction ◽  
Young Modulus ◽  
Palm Stearin ◽  
Binder System ◽  
Water Leaching ◽  
Space Holder ◽  
Porous Ti ◽  
Different Temperatures

Most Ti-6Al-4V implant used today are often much stiffer than human bone. However, the young modulus of those Ti-6Al-4V implants can be reduced through the formation of porous structure. Palm stearin binder system with an addition of sodium chloride as space holder has been established in the fabrication of porous Ti-6Al-4V. Thus, this paper focuses on the compressive mechanical properties of porous Ti-6Al-4V with utilization of palm stearin binder system along with sodium chloride (NaCl) as the space holder. The evaluated compositions consist of the powder volume fraction of 63vol% and 65vol%. The samples were compacted by thermal compacting machine at temperature of 160oC. Two different debinding processes involved, which are heptane solvent and water leaching. Then the samples were sintered up to three different temperatures, which are 1200oC, 1250oC and 1300oC. Mechanical properties of the porous Ti-6Al-4V were characterized by axial compression testing. The maximum compressive stress and Young’s modulus of the samples were determined to be 403.87MPa and 9.92GPa.

Porous Magnesium for Medical Applications - Influence of Powder Size on Mechanical Properties

2013 ◽  
Vol 592-593 ◽  
pp. 342-345 ◽  
Author(s):  
Jaroslav Čapek ◽  
Dalibor Vojtěch
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Ammonium Bicarbonate ◽  
Spherical Particles ◽  
Flexural Properties ◽  
Medical Applications ◽  
Powder Size ◽  
Magnesium Powder ◽  
Space Holder ◽  
Porous Magnesium

Porous magnesium materials appear to be promising candidates for scaffold production. In this work we prepared porous magnesium samples by powder metallurgy using ammonium bicarbonate as space-holder particles. We focused on the influence of the magnesium powder size and shape on product characteristics. Samples prepared using magnesium chips showed significantly worse flexural properties than samples with similar porosities prepared from an equi-axed magnesium powder. Therefore, we can conclude that spherical particles are more suitable for the preparation of porous objects by powder metallurgy.

scholarly journals Low-Temperature Mechanical Properties of High-Density and Low-Density Polyethylene and Their Blends

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1821
Author(s):  
Ildar I. Salakhov ◽  
Nadim M. Shaidullin ◽  
Anatoly E. Chalykh ◽  
Mikhail A. Matsko ◽  
Alexey V. Shapagin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Impact Strength ◽  
Relative Elongation ◽  
High Density ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Elongation At Break ◽  
Subzero Temperatures ◽  
Izod Impact

Low-temperature properties of high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and their blends were studied. The analyzed low-temperature mechanical properties involve the deformation resistance and impact strength characteristics. HDPE is a bimodal ethylene/1-hexene copolymer; LDPE is a branched ethylene homopolymer containing short-chain branches of different length; LLDPE is a binary ethylene/1-butene copolymer and an ethylene/1-butene/1-hexene terpolymer. The samples of copolymers and their blends were studied by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), 13С NMR spectroscopy, and dynamic mechanical analysis (DMA) using testing machines equipped with a cryochamber. It is proposed that such parameters as “relative elongation at break at −45 °C” and “Izod impact strength at −40 °C” are used instead of the ductile-to-brittle transition temperature to assess frost resistance properties because these parameters are more sensitive to deformation and impact at subzero temperatures for HDPE. LLDPE is shown to exhibit higher relative elongation at break at −45 °C and Izod impact strength at −20 ÷ 60 °C compared to those of LDPE. LLDPE terpolymer added to HDPE (at a content ≥ 25 wt.%) simultaneously increases flow properties and improves tensile properties of the blend at −45 °C. Changes in low-temperature properties as a function of molecular weight, MWD, crystallinity, and branch content were determined for HDPE, LLDPE, and their blends. The DMA data prove the resulting dependences. The reported findings allow one to understand and predict mechanical properties in the HDPE–LLDPE systems at subzero temperatures.

The Growth and Characterization of Germanium-Carbon Alloy Thin Films

1992 ◽  
Vol 270 ◽  
Author(s):  
Haojie Yuan ◽  
R. Stanley Williams
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Vacuum Chamber ◽  
Optical Band Gap ◽  
High Vacuum ◽  
Optical Absorption Spectroscopy ◽  
Alloy Thin Film ◽  
New Materials ◽  
X Ray

ABSTRACTThin films of pure germanium-carbon alloys (GexC1−x with x ≈ 0.0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0) have been grown on Si(100) and A12O3 (0001) substrates by pulsed laser ablation in a high vacuum chamber. The films were analyzed by x-ray θ-2θ diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), conductivity measurements and optical absorption spectroscopy. The analyses of these new materials showed that films of all compositions were amorphous, free of contamination and uniform in composition. By changing the film composition, the optical band gap of these semiconducting films was varied from 0.00eV to 0.85eV for x = 0.0 to 1.0 respectively. According to the AES results, the carbon atoms in the Ge-C alloy thin film samples has a bonding configuration that is a mixture of sp2 and sp3 hybridizations.

scholarly journals Comparison of Mechanical Properties of PMMA Disks for Digitally Designed Dentures

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1745
Author(s):  
Tamaki Hada ◽  
Manabu Kanazawa ◽  
Maiko Iwaki ◽  
Awutsadaporn Katheng ◽  
Shunsuke Minakuchi
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Water Sorption ◽  
Water Solubility ◽  
Flexural Modulus ◽  
Manufacturing Method ◽  
Heat Curing ◽  
Significant Difference ◽  
Cad Cam ◽  
Curing Method

In this study, the physical properties of a custom block manufactured using a self-polymerizing resin (Custom-block), the commercially available CAD/CAM PMMA disk (PMMA-disk), and a heat-polymerizing resin (Conventional PMMA) were evaluated via three different tests. The Custom-block was polymerized by pouring the self-polymerizing resin into a special tray, and Conventional PMMA was polymerized with a heat-curing method, according to the manufacturer’s recommended procedure. The specimens of each group were subjected to three-point bending, water sorption and solubility, and staining tests. The results showed that the materials met the requirements of the ISO standards in all tests, except for the staining tests. The highest flexural strength was exhibited by the PMMA-disk, followed by the Custom-block and the Conventional PMMA, and a significant difference was observed in the flexural strengths of all the materials (p < 0.001). The Custom-block showed a significantly higher flexural modulus and water solubility. The water sorption and discoloration of the Custom-block were significantly higher than those of the PMMA-disk, but not significantly different from those of the Conventional PMMA. In conclusion, the mechanical properties of the three materials differed depending on the manufacturing method, which considerably affected their flexural strength, flexural modulus, water sorption and solubility, and discoloration.

Mechanical properties of low-density paper

2020 ◽  
Vol 35 (1) ◽  
pp. 61-70
Author(s):  
Na Young Park ◽  
Young Chan Ko ◽  
Lili Melani ◽  
Hyoung Jin Kim
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Structural Change ◽  
Tensile Testing ◽  
Tensile Modulus ◽  
Gauge Length ◽  
Efficiency Factor ◽  
Low Density ◽  
Tensile Stiffness ◽  
Lower Tensile Strength

AbstractFor the mechanical properties of paper, tensile testing has been widely used. Among the tensile properties, the tensile stiffness has been used to determine the softness of low-density paper. The lower tensile stiffness, the greater softness of paper. Because the elastic region may not be clearly defined in a load-elongation curve, it is suggested to use the tensile modulus which is defined as the slope between the two points in the curve. The two points which provide the best correlation with subjective softness evaluation should be selected. Low-density paper has a much lower tensile strength, but much larger elongation at the break. It undergoes a continuous structural change during mechanical testing. The degree of the structural change should depend on tensile conditions such as the sample size, the gauge length, and the rate of elongation. For low-density paper, the tensile modulus and the tensile strength should be independent of each other. The structure efficiency factor (SEF) is defined as a ratio of the tensile strength to the tensile modulus and it may be used a guideline in developing superior low-density paper products.

Effect of Minor Additives on First Stage Graphitisation in White Cast Iron

1984 ◽  
Vol 34 ◽  
Author(s):  
P. L. Roy ◽  
A. K. Chakrabart ◽  
P. Banerjee
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Sodium Chloride ◽  
Yield Strength ◽  
White Cast Iron ◽  
Elemental Sulphur ◽  
Optimum Dose ◽  
White Iron ◽  
Kinetics Of ◽  
Strength And Ductility

ABSTRACTMinor additions (0.05-0.2 wt.%) of sodium chloride, hexachloroethane and elemental sulphur to commercial white iron melts have been found to enhance the kinetics of first stage graphitisation during subsequent annealing of white iron samples. The optimum dose of sodium chloride and hexachloroethane addition is around 0.1%. Yield strength and ductility of annealed test bars treated with NaCl or C2Cl6 compare favourably with those of untreated test bars. Sulphur treatment causes slight deterioration in mechanical properties. Fully grown nodules in both treated and untreated samples appear porous under SEM. Possible mechanisms of acceleration of graphitisation in the treated samples have been suggested.

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