Mechanical Properties of Transparent Polycrystalline Silicon Nitride

2006 ◽  
Vol 317-318 ◽  
pp. 305-308 ◽  
Author(s):  
Rak Joo Sung ◽  
Takafumi Kusunose ◽  
Tadachika Nakayama ◽  
Yoon Ho Kim ◽  
Tohru Sekino ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Nitride ◽  
Young’S Modulus ◽  
Fracture Strength ◽  
Polycrystalline Silicon ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Β Phase ◽  
Α Phase

A novel transparent polycrystalline silicon nitride was fabricated by hot-press sintering with MgO and AlN as additives. The mixed powder with 3 wt.% MgO and 9 wt.% AlN was sintered at 1900oC for 1 hour under 30 MPa pressure in a nitrogen gas atmosphere. Transparent polycrystalline silicon nitride was successfully fabricated. The mechanical properties such as density, hardness, young’s modulus, fracture strength and fracture toughness were evaluated. The effect of α/β phase on the mechanical properties of transparent polycrystalline silicon nitride was investigated. The properties were changed depending on the amount of α/β phase. The hardness and Young's modulus increased with increasing the volume fraction of α-phase fraction as a reflection of the higher hardness of α-phase Si3N4. The fracture toughness and fracture strength decreased with decreasing the volume fraction of β-phase Si3N4.

The Effects of Nb and Mo Addition on Microstructure and Mechanical Behaviour of Ti-6Al-4V Alloy

2017 ◽  
Vol 33 (1-2) ◽  
pp. 53 ◽  
Author(s):  
A. Kaouka ◽  
K. Benarous ◽  
A. Daas ◽  
S. A. Tsipas
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Young’S Modulus ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Vacuum Furnace ◽  
Processing Temperature ◽  
X Ray Diffraction ◽  
Β Phase ◽  
Equiaxed Grain

The effects of Nb and Mo addition, with different contents, on the microstructure and some mechanical properties of Ti-6Al-4V alloy were investigated. Treatments were performed at various high temperatures about 1200 and 1300 °C for 3h using vacuum furnace as first treatment and using an argon atmosphere as second treatment. The samples were characterized by X-ray diffraction and the influence of processing temperature on microstructure was studied, the microstructural evolution was evaluated by optical microscopy and SEM. The results revealed that the Nb and Mo elements added to the titanium alloy stabilized the β phase and changed the lattice parameters of α phase. Microstructural observations, phase analysis shown that Ti-6Al-4V alloy contain single phase and increasing Nb and Mo contents the equiaxed grain is refined, and reduction in the prior β grain size. Moreover, Nb/Mo addition up to 10 wt.% increases the volume fraction of β phase in the microstructure. Some mechanical properties such as hardness, Young's modulus and fracture toughness were achieved and tensile test was performed at room temperature. Experimental results revealed good mechanical properties including a low Young's modulus and high deformability, the hardness values of the alloy is about 350-570 HV and the fracture toughness values K<sub>IC</sub> are ranging from 16.8 MPa m<sup>1/2</sup> to 28.5 MPa m<sup>1/2</sup> depending on Nb/Mo contents.

Influence of Material Composition on Mechanical Properties and Fracture Behavior of Ceramic-Metal Composites

2005 ◽  
Vol 297-300 ◽  
pp. 1516-1521 ◽  
Author(s):  
Keiichiro Tohgo ◽  
Takayuki Kawaguchi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Young’S Modulus ◽  
Fracture Strength ◽  
Vickers Hardness ◽  
Fracture Behavior ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Metal Phase ◽  
Metal Composites

In order to estimate distribution of mechanical properties and fracture toughness in ceramic-metal functionally graded materials (FGMs), mechanical properties and fracture behavior have been investigated on non-graded ceramics-metal composites which correspond to each region of FGMs. The materials are fabricated by powder metallurgy using partially stabilized zirconia (PSZ) and stainless steel (SUS 304). Vickers hardness, Young’s modulus and bending fracture strength were examined on smooth specimens. The Vickers hardness of the composites continuously decreases with an increase in a volume fraction of SUS 304 metal phase, while the Young’s modulus and fracture strength exhibit low values in the composites with balanced composition of each phase. This suggests that the interfacial strength between the ceramic and metal phases is very low. Fracture toughness tests are conducted by three-point-bending on rectangular specimens with a sharp edgenotch. In contrast with the Young’s modulus and fracture strength, the fracture toughness obtained for the composites increases with an increase in a volume fraction of SUS 304 metal phase. The fracture toughness of the composites is slightly lower than that obtained previously by stable crack growth in a PSZ-SUS 304 FGM. The difference in fracture toughness between the composites and FGM seems to be attributed to the residual stress created during fabrication of the FGM.

Investigation of the Influence of Ti-Nb Alloy Composition on the Structure of the Ingots Produced by Arc Melting

2015 ◽  
Vol 1085 ◽  
pp. 307-311 ◽  
Author(s):  
Yurii Sharkeev ◽  
Zhanna G. Kovalevskaya ◽  
Qi Fang Zhu ◽  
Margarita A. Khimich ◽  
Evgeniy A. Parilov
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Alloy Composition ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Arc Melting ◽  
Α Phase

The results of investigation of the structure, physical and mechanical properties of the Ti-Nb alloy ingots with different composition obtained by arc melting are presented. X-ray diffraction and microstructural analyses were used. Microhardness was measured and the Young’s modulus of the alloys was evaluated. When the content of niobium in the alloy changes from 10 to 40 mass.%, phase composition of the alloy varies from α-and α'-phase (10 mass.% of Nb) to α'-, α''- and β-phases (25 mass.% of Nb), to the β-phase (40 mass.% of Nb). The alloy containing 40 mass.% Nb has the lowest Young’s modulus.

Characterization of Mechanical Properties of Silicon Nitride Thin Films for Space Applications

2003 ◽  
Vol 782 ◽  
Author(s):  
Wen-Hsien Chuang ◽  
Thomas Luger ◽  
Rainer K. Fettig ◽  
Reza Ghodssi
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Silicon Nitride ◽  
Young’S Modulus ◽  
Fracture Strength ◽  
Room Temperature ◽  
Young's Modulus ◽  
Space Environment ◽  
Bending Test ◽  
Space Applications

ABSTRACTMechanical properties of micro-electro-mechanical systems (MEMS) materials at cryogenic temperatures are investigated to extend MEMS devices into space applications. A helium-cooled measurement setup mimicking the outer space environment is developed and installed inside a focused-ion-beam (FIB) system. T-shape, low-stress LPCVD silicon nitride cantilevers suspended on a silicon substrate are fabricated as the test structures using bulk micromachining technique. A lead-zirconate-titanate (PZT) translator and a silicon diode are utilized as an actuator and a temperature sensor in the measurement setup, respectively. The resonant frequencies of an identical cantilever with different “milling masses” are measured to obtain the thickness and the Young's modulus. Additionally, a bending test is performed to determine the fracture strength. From the experiments, the Young's modulus of LPCVD silicon nitride thin films varies from 260.5 GPa ± 5.4 GPa at room temperature (298 K) to 266.6 GPa ± 4.1 GPa at 30 K, while the fracture strength ranges from 6.9 GPa ± 0.6 GPa at room temperature to 7.9 GPa ± 0.7 GPa at 30 K.

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.

Manufacturing and Measuring Mechanical Properties of Continuous Functionally Graded Beam

2021 ◽  
Vol 21 (2) ◽  
pp. 7-11
Author(s):  
Ahmed Mansoor Abbood ◽  
Haider K. Mehbes ◽  
Abdulkareem. F. Hasan
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Functionally Graded ◽  
High Concentration ◽  
Functionally Graded Beam ◽  
Low Concentration ◽  
Graded Material ◽  
Vertical Gravity

In this study, glass-filled epoxy functionally graded material (FGM) was prepared by adopting the hand lay-up method. The vertical gravity casting was used to produce a continuous variation in elastic properties. A 30 % volume fraction of glass ingredients that have mean diameter 90 μm was spread in epoxy resin (ρ = 1050 kg/m3). The mechanical properties of FGM were evaluated according to ASTM D638. Experimental results showed that a gradually relationship between Young’s modulus and volume fraction of glass particles, where the value of Young’s modulus at high concentration of glass particles was greater than that at low concentration, while the value of Poisson’s ratio at high concentration of glass particles was lower than that at low concentration. The manufacture of this FG beam is particularly important and useful in order to benefit from it in the field of various fracture tests under dynamic or cyclic loads.

scholarly journals Effects of CNT Addition on Mechanical Properties, Electric Conductivity and Oxidation Resistance of Al2O3-TiC Composite

2013 ◽  
Vol 761 ◽  
pp. 83-86
Author(s):  
Hideaki Sano ◽  
Junichi Morisaki ◽  
Guo Bin Zheng ◽  
Yasuo Uchiyama
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Electric Conductivity ◽  
Young’S Modulus ◽  
Oxidation Resistance ◽  
Young's Modulus ◽  
Tic Particle

Effects of carbon nanotubes (CNT) addition on mechanical properties, electric conductivity and oxidation resistance of CNT/Al2O3-TiC composite were investigated. It was found that flexural strength, Young’s modulus and fracture toughness of the composites were improved by addition of more than 2 vol%-CNT. In the composites with more than 3 vol%-CNT, the oxidation resistance of the composite was degraded. In comparison with Al2O3-26vol%TiC sample as TiC particle-percolated sample, the Al2O3-12vol%TiC-3vol%CNT sample, which is not TiC particle-percolated sample, shows almost the same mechanical properties and electric conductivity, and also shows thinner oxidized region after oxidation at 1200°C due to less TiC in the composite.

Cellulose Whiskers Micro-Fibers Effect in the Mechanical Proprieties of PP and PLA Composites Fibers Obtained by Spinning Process

2011 ◽  
Vol 146 ◽  
pp. 12-26 ◽  
Author(s):  
A. Gherissi ◽  
R.Ben Cheikh ◽  
E. Dévaux ◽  
Fethi Abbassi
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Tensile Tests ◽  
Advanced Materials ◽  
Uniaxial Tensile ◽  
Failure Resistance ◽  
Cellulose Whiskers ◽  
Limit Strength

In this study, we present the manufacturing process of two new composites materials in the form of long fibers of polylactic-acid (PLA) or polypropylene (PP), reinforced by cellulose whiskers micro-fibers loads. In order to evaluate the mechanical properties of these advanced materials, a several uniaxial tensile tests were carried out. The PP and the PLA have initially been spinning without the addition of cellulose whiskers micro-fibers. In order to study the effects of cellulose whiskers micro-fibers reinforcements in the Mechanical behavior of the PLA and PP filaments, we determinate the proprieties of these advanced material from the tensile results. For the PP composite filaments material case, the whiskers reinforcement increases Young's modulus and failure resistance, but it reduces the limit strength failure. For the PLA composites the addition of 1% wt of cellulose whiskers from the total volume fraction of the material, increase the Young’s modulus more than 50% and a decrease of the failure resistance and the limit strength of composite. The obtained composites fibers are very rigid and brittle. What follows, that the addition of cellulose whiskers micro fibers in PP matrix, provides mechanical properties more convenient compared to the PLA matrix.

Phase Stability and Mechanical Properties of Ti-Cr-Sn-Zr Alloys Containing a Large Amount of Zr

2016 ◽  
Vol 879 ◽  
pp. 1344-1349 ◽  
Author(s):  
Yonosuke Murayama ◽  
Erdnechuluun Enkhjavkhlan ◽  
Akihiko Chiba
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Deformation Behavior ◽  
Single Phase ◽  
Young's Modulus ◽  
Martensitic Structure ◽  
Β Phase ◽  
Microstructural Transition ◽  
Zr Alloy ◽  
Zr Alloys

The Young’s modulus of Ti-Cr-Sn-Zr alloy varies with the composition of Cr, Sn and Zr, in which the elements act as β stabilizers. Some Ti-Cr-Sn-Zr alloys show very low Young’s modulus under 50GPa. The amount of Zr in alloys with very low Young's modulus increases with the decrease of Cr. We investigated the Young’s modulus and deformation behavior of Ti-xCr-Sn-Zr (x=0~1mass%) alloys containing a large amount of Zr. The quenched microstructure of Ti-Cr-Sn-Zr alloys changes from martensitic structure to β single-phase structure if the amounts of β stabilized elements are increased. The Ti-Cr-Sn-Zr alloys with compositions close to the transitional composition of microstructure from martensite to β phase show minimum Young’s modulus. The clear microstructural transition disappears and the minimum Young’s modulus increases if the amount of Cr becomes too small. In Ti-Cr-Sn-Zr alloys containing a large amount of Zr, Young’s modulus depends on β phase that is intermingled with martensite.

Determination of mechanical properties of FFF 3D printed material by assessing void volume fraction, cooling rate and residual thermal stresses

2019 ◽  
Vol 25 (10) ◽  
pp. 1661-1683 ◽  
Author(s):  
Rafael Quelho de Macedo ◽  
Rafael Thiago Luiz Ferreira ◽  
Kuzhichalil Jayachandran
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Young’S Modulus ◽  
Thermal Stresses ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Void Volume Fraction ◽  
Void Volume ◽  
Temperature Fields ◽  
Content Type

Purpose This paper aims to present experimental and numerical analyses of fused filament fabrication (FFF) printed parts and show how mechanical characteristics of printed ABS-MG94 (acrylonitrile butadiene styrene) are influenced by the void volume fraction, cooling rate and residual thermal stresses. Design/methodology/approach Printed specimens were experimentally tested to evaluate the mechanical properties for different printing speeds, and micrographs were taken. A thermo-mechanical finite element model, able to simulate the FFF process, was developed to calculate the temperature fields in time, cooling rate and residual thermal stresses. Finally, the experimental mechanical properties and the microstructure distribution could be explained by the temperature fields in time, cooling rate and residual thermal stresses. Findings Micrographs revealed the increase of void volume fraction with the printing speed. The variations on voids were associated to the temperature fields in time: when the temperatures remained high for longer periods, less voids were generated. The Young's Modulus of the deposited filament varied according to the cooling rate: it decreased when the cooling rate increased. The influence of the residual thermal stresses and void volume fraction on the printed parts failure was also investigated: in the worst scenarios evaluated, the void volume fraction reduced the strength in 9 per cent, while the residual thermal stresses reduced it in 3.8 per cent. Originality/value This work explains how the temperature fields can affect the void volume fraction, Young's Modulus and failure of printed parts. Experimental and numerical results are shown. The presented research can be used to choose printing parameters to achieve desired mechanical properties of FFF printed parts.

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