Microstuctural and Mechanical Properties of Zirconia-Silica-Hydroxyapatite Composite for Biomedical Applications

2014 ◽  
Vol 631 ◽  
pp. 156-159
Author(s):  
Aliye Arabaci ◽  
Nazlican Yüksel ◽  
Nermin Demirkol
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Biomedical Applications ◽  
Sintering Behavior ◽  
Microstructural Characteristics ◽  
Calcium Phosphate Ceramic ◽  
Hydroxyapatite Composite ◽  
Different Temperatures ◽  
Zirconia Powders

Hydroxyapatite is a calcium phosphate ceramic that is used as a biomaterial. It has been studied extensively as a candidate biomaterial for prosthetic applications. Hydroxyapatite (HA) does not have the mechanical strength to enable it to succeed in long term load bearing applications. Therefore, Its mechanical properties may be improved with addition of zirconia powders. The aim of this study is to improve the mechanical properties of the hydroxyapatite by producing composite material including zirconia and silica powders. Therefore, hydroxyapatite was mixed with 5 wt% zirconia, 5 wt% silica powders and then this pressed mixture were sintered at different temperatures (1100-1300°C). The sintering behavior, microstructural characteristics and mechanical properties were investigated.

scholarly journals Experimental Study on the Creep Behavior of Red Sandstone under Low Temperatures

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Yongjun Song ◽  
Leitao Zhang ◽  
Huimin Yang ◽  
Jianxi Ren ◽  
Yongxin Che
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Deformation Characteristics ◽  
Red Sandstone ◽  
Rock Samples ◽  
Uniaxial Creep ◽  
Deformation Properties ◽  
Accelerated Creep ◽  
Different Temperatures

In cold regions, the deformation characteristics and long-term mechanical properties of rocks under low-temperature conditions are considerably different from those in other regions. To study the deformation characteristics and long-term mechanical properties of rocks in a low-temperature environment and the effect of different temperatures, we perform a multilevel loading-unloading uniaxial creep test on red sandstone samples and obtain the creep curves at different temperatures (20°C, −10°C, and −20°C). The results demonstrate that the total strain at each temperature can be divided into instantaneous and creep strains; the instantaneous strain includes instantaneous elastic and plastic strains, and the creep strain includes viscoelastic and viscoplastic strains. Temperature has a significant effect on the deformation properties of red sandstone. A decrease in temperature reduces the instantaneous and creep deformations of the rocks at all levels of stress. In addition, a decrease in temperature exponentially attenuates the total creep and viscoplastic strains of the rocks. 0°C is a critical point for the reduction of the total creep and viscoplastic strains of the rocks. When the temperature is greater than 0°C, the total creep and viscoplastic strains of the rocks decrease rapidly and linearly with decrease in temperature; however, when the temperature is less than 0°C, the decrease in the total creep and viscoplastic strains of the rocks is slow. The steady-state creep rate of the rock samples decreases with decrease in temperature, whereas the creep duration increases with decrease in temperature, especially in the case of the accelerated creep stage. The accelerated creep durations of the rock samples S4 (20°C) and S7 (–10°C) are 0.07 h and 0.23 h, respectively.

scholarly journals Sintering Behavior of a Six-Oxide Silicate Bioactive Glass for Scaffold Manufacturing

2020 ◽  
Vol 10 (22) ◽  
pp. 8279
Author(s):  
Elisa Fiume ◽  
Gianpaolo Serino ◽  
Cristina Bignardi ◽  
Enrica Verné ◽  
Francesco Baino
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Tissue Repair ◽  
Sintering Temperature ◽  
Thermal Analyses ◽  
Three Dimensional ◽  
Sintering Behavior ◽  
Porous Scaffolds ◽  
Bioactive Glasses ◽  
Different Temperatures

The intrinsic brittleness of bioactive glasses (BGs) is one of the main barriers to the widespread use of three-dimensional porous BG-derived bone grafts (scaffolds) in clinical practice. Among all the available strategies for improving the mechanical properties of BG-based scaffolds, strut densification upon sintering treatments at high temperatures represents a relatively easy approach, but its implementation might lead to undesired and poorly predictable decrease in porosity, mass transport properties and bioactivity resulting from densification and devitrification phenomena occurring in the material upon heating. The aim of the present work was to investigate the sinter-crystallization of a highly bioactive SiO2-P2O5-CaO–MgO–Na2O–K2O glass (47.5B composition) in reference to its suitability for the fabrication of bonelike foams. The thermal behavior of 47.5B glass particles was investigated upon sintering at different temperatures in the range of 600–850 °C by means of combined thermal analyses (differential thermal analysis (DTA) and hot-stage microscopy (HSM)). Then, XRD measurements were carried out to identify crystalline phases developed upon sintering. Finally, porous scaffolds were produced by a foam replica method in order to evaluate the effect of the sintering temperature on the mechanical properties under compression loading conditions. Assessing a relationship between mechanical properties and sintering temperature, or in other words between scaffold performance and fabrication process, is a key step towards the rationale design of optimized scaffolds for tissue repair.

Flip-Chip Ball Grid Array Lead-Free Solder Joint Under Reliability Test

2005 ◽  
Vol 127 (4) ◽  
pp. 446-451 ◽  
Author(s):  
Ming-Hwa R. Jen ◽  
Lee-Cheng Liu ◽  
Jenq-Dah Wu
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Service Time ◽  
Flip Chip ◽  
Failure Modes ◽  
Mechanical Responses ◽  
Operational Life ◽  
Different Temperatures ◽  
Free Solder

The work is aimed to investigate the mechanical responses of bare dies of the combination of pure tin∕Al–NiV–Cu Under bump metallization (UBM) and packages of pure tin∕Al–NiV–Cu UBM/substrate of standard thickness of aurum. The mechanical properties under multiple reflow and long term high temperature storage test (HTST) tests at different temperatures and the operational life were obtained. A scanning electron microscope was used to observe the growth of IMC and the failure modes in order to realize their reaction and connection. From the empirical results of bare dies, the delamination between IMC and die was observed due to the tests at 260 °C multiple reflow. However, their mechanical properties were not affected. Nevertheless, the bump shear strength of bare dies were decreased by HTST tests. In package, all the results of mechanical properties by multiple reflow test and HTST test were significantly lowered. It was shown that the adhesion between bump and die reduced obviously as tests going on. As for high temperature operational life test in the conditions of 150 °C and 320 mA (5040A∕cm2), the average stable service time of the package was 892 h, and the average ultimate service time of the package was 1053 h.

scholarly journals The influence of untreated sugarcane bagasse ash on the microstructural and mechanical properties of mortars

2018 ◽  
Vol 68 (329) ◽  
pp. 148 ◽  
Author(s):  
M. A. Maldonado-García ◽  
U. I. Hernández-Toledo ◽  
P. Montes-García ◽  
P. L. Valdez-Tamez
Keyword(s):  
Mechanical Properties ◽  
Sugarcane Bagasse ◽  
Composition Analysis ◽  
X Ray Diffraction ◽  
Microstructural Characteristics ◽  
X Ray ◽  
Physical Absorption ◽  
Sugarcane Bagasse Ash ◽  
Xrd Techniques

This study investigated the effects of the addition of untreated sugarcane bagasse ash (UtSCBA) on the microstructural and mechanical properties of mortars. The SCBA was sieved for only five minutes through a No. 200 ASTM mesh, and fully characterized by chemical composition analysis, laser ray diffraction, the physical absorption of gas, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Mortar mixtures with 0, 10 and 20% UtSCBA as cement replacement and a constant 0.63 water/cementitious material ratio were prepared. Fresh properties of the mortars were obtained. The microstructural characteristics of the mortars at 1, 7, 28, 90 and 600 days were evaluated by SEM and XRD. The compressive strengths of the mortars at the same ages were then obtained. The results show that the addition of 10 and 20% UtSCBA caused a slight decrease in workability of the mortars but improved their microstructure, increasing the long-term compressive strength.

Dynamic Stability of Multi-Functional Composite Developed for Application in Permanent Way of Prague Underground

2018 ◽  
Vol 760 ◽  
pp. 147-151
Author(s):  
Karel Kolář ◽  
Jiří Litoš ◽  
Pavel Reiterman ◽  
Miroslav Petrtýl
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Dynamic Stability ◽  
Dynamic Loading ◽  
Rapid Evolution ◽  
Steel Fibers ◽  
Laboratory Model ◽  
Transportation Industry ◽  
Reference Mixture

There are described properties of hardening multi-functional silicate composite during its long-term dynamical loading in the paper. Studied composite was developed for special application in permanent way structure in Prague underground. Dynamic loading was carried out on the laboratory model, in which the composite was applied as a bench of the rail anchoring. Due to loading in early ages was also studied the option of steel fibers addition. Results obtained confirmed impressive potential for practical use during new tracks construction, and quick repairs as well, because of rapid evolution of mechanical properties and sufficient resistance to dynamic loading. Silicate composite with fibers addition had better mechanical properties, however significant improvement during dynamic loading was not recorded in comparison with the reference mixture without fibers. Generally, new composite material confirmed great potential for practical use in transportation industry.

scholarly journals Natural Aging Behavior Of Friction Stir Welded Al-Zn-Mg-Cu Aluminum Alloys

2015 ◽  
Vol 60 (2) ◽  
pp. 875-879
Author(s):  
I. Kalemba ◽  
M. Kopyściański ◽  
C. Hamilton ◽  
S. Dymek
Keyword(s):  
Mechanical Properties ◽  
Material Flow ◽  
Flow Model ◽  
Natural Aging ◽  
Hardness Profile ◽  
Aging Behavior ◽  
Microstructural Characteristics ◽  
Friction Stir ◽  
Joining Process

Abstract The long term natural aging behavior of friction stir welded aluminum 7136-T76 and 7042 T6 extrusions was investigated. The microstructural characteristics and mechanical properties in the as-welded and six years naturally aged conditions were studied and correlated to a coupled thermal/material flow model of the joining process. Hardness profiles for the 7136 alloy taken along the mid-plane thickness of the workpiece displayed the characteristic W-shape. With natural aging, hardness recovery occurred on both sides of the weld, but the position of the hardness minima, particularly on the advancing side, shifted away from the weld centerline. The hardness profile for the 7042 alloy displayed U-shape in the as-welded condition and W-shape after natural aging. The hardness behavior upon natural aging correlated to the temperature profile developed during welding and the degree to which phase dissolution occurred in the regions adjacent to the stir zone.

scholarly journals Sintering Temperature and Applied Pressure Effect on Manufacturing Ni-Cr Based Composite Material.

2020 ◽  
Vol 9 (3) ◽  
pp. 1428-1433
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Pressure Effect ◽  
Sintering Temperature ◽  
Applied Pressure ◽  
Vital Role ◽  
Nickel Chromium ◽  
Different Temperatures ◽  
Highly Porous ◽  
Highly Porous Material

Mechanical Property of Nickel-Chromium composite investigated with different parameters. Green pallets (composite) were manufactured under the different pressure (220MPa, 275MPa and 330MPa) and such pallet sintering in two different temperatures (9000C and 10000C). The result indicate that the properties of the composite increases with increasing pressure and also with increasing sintering temperature for Ni-Cr based composite. Porosity plays a vital role in mechanical properties of composite and it present between maximum 4.304% to minimum 1.865%. For highly porous material, mechanical properties are minimum than lower porous composite material. The result of the study reveals that the properties of Ni-Cr based composite improved for 330MPa pressure and 1000oC temperature. Thus there is need to consider these aspect while manufacturing the composite material to have a good mechanical or Tribological properties.

Freezing Induced Microstructural Change of Collagen Matrix

2007 ◽  
Author(s):  
Bumsoo Han ◽  
Jeffrey D. Miller ◽  
Jun K. Jung
Keyword(s):  
Functional Properties ◽  
Biomedical Applications ◽  
Collagen Matrix ◽  
Tissue Type ◽  
Cellular Viability ◽  
Short Term ◽  
Microstructural Characteristics ◽  
High Viability ◽  
Induced Changes

Freezing of biological tissue occurs in many modern biomedical applications. These include cryosurgery for cancer, cryoablation for cardiac arrhythmia, cryoplasty for restenosis, and cryopreservation of native and engineered biomaterials. While the short-term success of these applications depends on the cellular viability — low viability for the therapeutic applications, and high viability for the preservation applications, the long-term success is determined by whether the functional properties of tissue are controlled as well as the viability. This becomes more important as the freezing-based technologies begin to be applied to larger and more complex biomaterials. However, the effects of freezing on these functional properties are rarely understood. Although several studies have been done on the freezing-induced change of the mechanical properties, the results are highly tissue-type dependent and the underlying biophysical mechanisms are poorly understood. Since the functional properties are associated with or often determined by the microstructural characteristics of the extracellular matrix (ECM), it is hypothesized that freezing-induced changes on the ECM microstructure affect the post-thaw functional properties. Thus, in this study, microstructural changes of collagen matrix were investigated using scanning electron microscopy and image analysis.

The Rehbinder effect in tests of superalloys in contact with molten salts

2021 ◽  
Vol 87 (10) ◽  
pp. 54-62
Author(s):  
L. B. Getsov ◽  
M. Yu. Balandina ◽  
A. I. Grishchenko ◽  
A. B. Laptev ◽  
A. I. Puzanov
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Molten Salts ◽  
Term Strength ◽  
Initial State ◽  
Rehbinder Effect ◽  
Corrosive Media ◽  
Term Operation ◽  
Different Temperatures

The results of the Rehbinder effect manifestation during testing of superalloys in contact with corrosive media containing Na2SO4 + NaCl are discussed. We present the experimental study of the effect of salts containing chlorine and sulfur on the mechanical properties and long-term strength of single crystal and powder nickel-based superalloys at high temperatures. The practical value of the work is associated with the possible operation of gas turbine parts in conditions of ingress of the particles containing chlorine, sulfur and sodium into the flow path. A simplified (compared to a previously used) procedure of testing wrought alloys for long-term strength in molten salts is developed. A comparative study of the mechanical properties and long-term strength of a single crystal superalloy in the initial state (previously damaged by corrosion of different duration) and being in contact with salts during testing is carried out. Due to the large scatter of experimental data, the method of lower envelopes has been proposed and implemented to determine the guaranteed values of the long-term strength. It is shown that the guaranteed values of the long-term strength at different temperatures and test durations can decrease by 2.5 – 5.0 times in the presence of salts. Metallographic studies of the nature of damage and destruction of samples are carried out. The revealed decrease in the long-term strength of heat-resistant alloys in contact with salts is interpreted as the Rehbinder effect and not as a manifestation of the effect of stress corrosion cracking. A methodology for using the obtained test results with a duration of up to several thousand hours in highly aggressive environments is proposed to predict the long-term strength in relation to long-term operation (tens of thousands of hours) under conditions of relatively low salt loads.

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