The Mechanical Properties of a Novel Si3N4-Amorphous Si3N4 Composite

1992 ◽  
Vol 287 ◽  
Author(s):  
Ivar E. Reimanis ◽  
J. J. Petrovic ◽  
H. Suematsu ◽  
T. E. Mitchell ◽  
O. S. Leung
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Heat Treating ◽  
Two Phase ◽  
Transmission Electron ◽  
Amorphous Si ◽  
The Relationship ◽  
Amorphous Si3n4

ABSTRACTThe hardness and fracture toughness of a model two-phase composite consisting of crystalline Si3N4 particles in a matrix of amorphous Si3N4 are examined. The composite is created by heat treating high purity, partially amorphous CVD Si3N4 in N2 for various times and temperatures in order to induce crystallization of the a phase. Microindentation tests at temperatures up to 1200 °C are conducted to evaluate the high temperature hardness and fracture toughness. The role of the microstructure is examined using optical and transmission electron microscopy. Finally, the relationship between the microstructure and the mechanical properties is discussed.

The Dislocation Patterns in Deformed Metals: Dislocation Densities, Distributions and Related Misorientations

2007 ◽  
Vol 550 ◽  
pp. 193-198
Author(s):  
Edgar F. Rauch ◽  
G. Shigesato
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Dislocation Substructure ◽  
Metals And Alloys ◽  
The Past ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Broad Variety ◽  
The Relationship

The dislocation substructure that appears in deformed metals and alloys have been extensively investigated in the past by transmission electron microscopy (TEM). They are known to form a broad variety of microstructures. These substructures are characterized by three main parameters, namely the density of the dislocations that are trapped in the tangles, their degree of patterning and the misorientation between the cells. The aim of the present work is to investigate the relationship between these features and the mechanical properties of the material.

Effect of Annealing Temperature on Microstructure and Properties of Ultra Purified Ferritic Stainless Steel Containing Copper

2018 ◽  
Vol 913 ◽  
pp. 270-276
Author(s):  
Hong Xiang Yin ◽  
Yi Wu ◽  
Ai Min Zhao ◽  
Zheng Zhi Zhao ◽  
Qiu Qin Fu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Annealing Temperature ◽  
Texture Evolution ◽  
Fiber Texture ◽  
Transmission Electron ◽  
Back Scattering ◽  
Higher Temperature ◽  
Means Of Transmission ◽  
The Relationship

The effects of annealing temperature on microstructure, mechanical properties, formability, and texture evolution were analyzed in the article. The microstructure of the steel obtained through different annealing processes were investigated by means of transmission electron microscopy; The micro texture of steel was measured by using electron back scattering diffraction analysis; The relationship between Cu precipitates and matrix was analyzed by using the selected area diffraction technology. The results show that when annealing temperature was 700 ~ 850 °C, the yield strength and tensile strength first decreased slightly and then increased, while the elongation accordingly first increased then decreased slightly. The best mechanical property and formability were obtained at 800 °C. Cu precipitates reduced with the increase of annealing temperature and it accorded with K - S relationship with matrix. The grains near the {111} < 112 > orientation grew up selectively. The higher the temperature, the more the γ fiber texture content. But at higher temperature (850 °C), γ texture was damaged and the content was reduced.

scholarly journals Contributions of Electron Microscopy to the Understanding of Reactions on Compound Semiconductor Surfaces

1985 ◽  
Vol 62 ◽  
Author(s):  
T. Sands
Keyword(s):  
Electron Microscopy ◽  
Rutherford Backscattering Spectrometry ◽  
Compound Semiconductor ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Glancing Angle ◽  
Semiconductor Substrates ◽  
The Relationship ◽  
Minimum Quality

ABSTRACTReacted films on compound semiconductor substrates present challenging materials characterization problems which often require the application of transmission electron microscopy (TEM) techniques. In this paper, both the problem - solving potential of the TEM techniques and the limits imposed by preparation of thin film/compound semiconductor TEM specimens are discussed. Studies of the Ni/GaAs, CuCl(aq)/CdS and Pd/GaAs reactions exemplify the role of TEM in identifying and determining the spatial distribution of interface - stabilized polymorphs and new ternary phases (e.g. tetragonal Cu2S, Ni3GaAs and PdxGaAs). These examples also serve to clarify the relationship between TEM and complementary analysis techniques such as Rutherford backscattering spectrometry, Auger electron spectroscopy and glancing-angle x-ray diffraction. In particular, it is argued that a combination of (1) high-spatial-resolution information obtained by TEM and (2) an indication of the “average” behavior provided by data from a complementary characterization technique provide the minimum quality and quantity of data necessary to understand most reactions on compound semiconductor substrates.

Influence of Al-Content on the Microstructure and Mechanical Properties in ZrAlN Coatings

2014 ◽  
Vol 1004-1005 ◽  
pp. 778-783 ◽  
Author(s):  
Xiao Ying Zhu ◽  
Jun Du ◽  
Gui Min Liu ◽  
Xiao Hui Zheng
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Phase Structure ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Al Content ◽  
Microstructure And Mechanical Properties ◽  
Transmission Electron ◽  
Indentation Methods

Zirconium aluminum nitride coatings have been deposited onto Ti-6Al-4V substrates by reactive magnetron sputtering in order to investigate the influence of Al-content on the microstructure and mechanical properties. The morphology and microstructure of the coatings were investigated by field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Nanoindentation and Vicker’s indentation methods were employed to measure the hardness and toughness of the coatings, respectively. The results show that a structure of single cubic phase with twinning is formed at Al content of x ≤ 0.23, and a two-phase structure of hexagonal and cubic phase is formed at Al content of x ≥ 0.47. Hardness and toughness of the Zr1-xAlxN coatings show similar tendency with the increasing of Al-content. Both of them reach the maximum values at x=0.23 and drop to the minimum values at x=0.47, after that, they slightly increase with the increasing Al-content. The enhanced hardness and toughness achieved at x=0.23 is ascribed not only to single cubic phase structure but also to twinning structure.

Mechanical properties of hot isostatically pressed Si3N4 and Si3N4/SiC composites

1993 ◽  
Vol 8 (3) ◽  
pp. 626-634 ◽  
Author(s):  
O. Unal ◽  
J.J. Petrovic ◽  
T.E. Mitchell
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Hardness ◽  
High Resolution Electron Microscopy ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Sic Whiskers ◽  
Sic Composites ◽  
Increasing Temperature

The mechanical properties of hot isostatically pressed monolithic Si3N4 and Si3N4−20 vol. % SiC composites have been studied by microindentation at temperatures up to 1400 °C. Indentation crack patterns and microstructures have been examined by optical microscopy, scanning electron microscopy, and transmission electron microscopy. It is shown that dense Si3N4 base materials can be synthesized by HIPing without densification aids. Both the monolithic Si3N4 and the Si3N4/SiC composites exhibit high hardness values which gradually decrease with increasing temperature. Both types of material show low fracture toughness values apparently because of strong interfacial bonding. On the other hand, the fracture toughness of the composite is about 40% higher than that of the monolithic material, due to the presence of the 20 vol. % SiC whiskers. A crack deflection/debonding mechanism is likely to be responsible for the higher toughness observed in the composite. High resolution electron microscopy shows that the grain boundaries in both samples contain a thin SiO2 layer.

Synthesis and Characterization of CdSe Microspheres via Solvothermal Process

2010 ◽  
Vol 654-656 ◽  
pp. 1142-1145
Author(s):  
Juan Yang ◽  
Chuang Liang Zang ◽  
Xiao Nong Cheng
Keyword(s):  
Electron Microscopy ◽  
Heat Treating ◽  
Reducing Agent ◽  
Wurtzite Structure ◽  
Mixed Solution ◽  
X Ray Diffraction ◽  
Zinc Blende ◽  
Transmission Electron

CdSe particles with the wurtzite structure have been synthesized via solvothermal method using a mixed solution of triethylenetetramine (TETA) and de-ionized water (DIW) without adding a reducing agent. It was found that the ball-like CdSe precursor with the zinc-blende phase could be transformed to the wurtzite structure after heat-treating at 580 °C in Ar atmosphere and the obtained microspheres were composed of small CdSe particles. The experimental results were compared with that obtained without TETA and it was speculated that TETA in the mixed solution played a role of reducing agent and solvent. Both the as-prepared products and the annealed powders were systematically characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared absorbance spectroscopy (FTIR).

Mo-B-C and Ta-B-C Nanostructured Layers with Promising Fracture Toughness

2016 ◽  
Vol 368 ◽  
pp. 107-110 ◽  
Author(s):  
Jiří Buršík ◽  
Ivo Kuběna ◽  
Vilma Buršíková ◽  
Pavel Souček ◽  
Lukáš Zábranský ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Transmission Electron Microscopy ◽  
Cross Sections ◽  
Fracture Resistance ◽  
Ion Beam ◽  
Transmission Electron ◽  
Focussed Ion Beam ◽  
Nanostructured Layers

X-B-C (X=Mo, Ta) layers prepared by magnetron sputtering were tested. Mechanical properties were characterized by means of nanoindentation experiments in both the static and the dynamic loading regime. The results were correlated with observations of the microstructure under indentation prints by means of scanning and transmission electron microscopy on cross sections prepared using a focussed ion beam. An excellent fracture resistance of prepared nanostructured coatings was found.

scholarly journals Study on the Relationships between Microscopic Cross-Linked Network Structure and Properties of Cyanate Ester Self-Reinforced Composites

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 950
Author(s):  
Hongtao Cao ◽  
Beijun Liu ◽  
Yiwen Ye ◽  
Yunfang Liu ◽  
Peng Li
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
The Self ◽  
Reinforced Composites ◽  
Two Phase ◽  
Reinforced Composite ◽  
Transmission Electron ◽  
The Matrix ◽  
Ft Ir ◽  
The Cross

Bisphenol A dicyanate (BADCy) resin microparticles were prepared by precipitation polymerization synthesis and were homogeneously dispersed in a BADCy prepolymer matrix to prepare a BADCy self-reinforced composites. The active functional groups of the BADCy resin microparticles were characterized by Fourier transform infrared (FT-IR) spectroscopy. The results of an FT-IR curve showed that the BADCy resin microparticles had a triazine ring functional group and also had an active reactive group -OCN, which can initiate a reaction with the matrix. The structure of the BADCy resin microparticles was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). From the TEM results, the BADCy resin microparticles dispersed in the solvent were nano-sized and distributed at 40–60 nm. However, from the SEM results, agglomeration occurred after drying, the BADCy resin particels were micron-sized and distributed between 0.3 μm and 0.6 μm. The BADCy resin prepolymer was synthesized in our laboratory. A BADCy self-reinforced composite was prepared by using BADCy resin microparticles as a reinforcement phase. This corresponds to a composite in which the matrix and reinforcement phase are made from different morphologies of the same monomer. The DSC curve showed that the heat flow of the microparticles is different from the matrix during the curing reaction, this means the cured materials should be a microscopic two-phase structure. The added BADCy resin microparticles as reaction sites induced the formation of a more complete and regular cured polymer structure, optimizing the cross-linked network as well as increasing the interplay between the BADCy resin microparticles and prepolymer matrix. Relative to the neat BADCy resin material, the tensile strength, flexural strength, compressive strength and impact strength increased by 98.1%, 40.2%, 27.4%, and 85.4%, respectively. A particle toughening mechanism can be used to explain the improvement of toughness. The reduction in the dielectric constant showed that the cross-linked network of the self-reinforced composite was more symmetrical and less polar than the neat resin material, which supports the enhanced mechanical properties of the self-reinforced composite. In addition, the thermal behavior of the self-reinforced composite was characterized by thermogravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMTA). The results of DMTA also establishes a basis for enhancing mechanical properties of the self-reinforced composite.

Effect of Aging Treatment on Microstructure and Mechanical Properties of a Two-Phase Titanium Alloy

2010 ◽  
Vol 654-656 ◽  
pp. 851-854
Author(s):  
Miao Song ◽  
Jia Feng Lei ◽  
Ying Jie Ma ◽  
Yu Yin Liu
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Quantitative Analysis ◽  
Aging Temperature ◽  
Aging Treatment ◽  
Large Area ◽  
Two Phase ◽  
Rich Phase ◽  
Α Phase ◽  
Transmission Electron

In present work, microstructure of Ti-6Al-2Mo-1.5Cr-2Sn-2Zr-1V-0.15Si-0.4Fe alloy as a function of aging temperature was investigated using optical microscopy, scanning electron microscopy (SEM), x-ray diffraction (XRD) and transmission electron microscopy (TEM).Three types of precipitates were found in this alloy, they were α2 phase (Ti3Al), silicides, and Sn rich phase. Ti3Al were observed in all aged specimens covering a range 500-740°C. A method of quantitative analysis toward α2 based on high resolution images and Flourier transformation is used. The results showed that the ordering in α phase was highly related to the property of fracture toughness. Silicides were first found at 580°C ageing and later determined in the formulate (Ti5+xZr3-x)Si3 in the specimens aged at 740°C, and they were found to influent the fracture toughness significantly. The Sn rich phase was emerged with large area during the 780°C aging. And its direct correlation to property was not found. The density of acicular α phase was found almost invariable by calculating through the modification XRD quantitative analysis during the elevated aging temperature.

scholarly journals Effect of Alloying Additions on Microstructure, Mechanical and Magnetic Properties of Rapidly Cooled Bulk Fe-B-M-Cu (M = Ti, Mo and Mn) Alloys

2021 ◽  
Author(s):  
Mariusz Hasiak ◽  
Marzena Tkaczyk ◽  
Amadeusz Łaszcz ◽  
Jacek Olszewski
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Magnetic Properties ◽  
Elastic Modulus ◽  
Instrumented Indentation ◽  
Soft Magnetic ◽  
Alloying Additions ◽  
Transmission Electron ◽  
Wide Range ◽  
The Relationship

AbstractThe influence of alloying additions on the microstructure, mechanical, and magnetic properties of bulk Fe79B20Cu1, Fe79B16Ti4Cu1, Fe79B16Mo4Cu1 and Fe79B16Mn4Cu1 (at. pct) alloys was investigated. Nanocrystalline samples in the form of 3 mm rods were prepared directly by suction casting without additional heat treatment. Mössbauer spectroscopy, transmission electron microscopy and scanning electron microscopy studies confirmed that the investigated alloys consist α-Fe and Fe2B nanograins embedded in an amorphous matrix. The addition of alloying elements, such as Ti, Mo and Mn to Fe79B20Cu1 alloy increases the amount of amorphous phase and decreases the presence of Fe2B phase in all examined alloys. The mechanical properties of the samples, such as hardness, elastic modulus, and elastic energy ratio, were analysed by an instrumented indentation technique performed on a 12 × 12 nanoindentation grid. These tests allowed to characterise the mechanical properties of the regions observed in the same material. For the Fe79B20Cu1 alloy, the hardness of 1508 and 1999 HV, as well as Young’s modulus of 287 and 308 GPa, were estimated for the amorphous- and nanocrystalline-rich phase, respectively. The addition of Ti, Mo, and Mn atoms leads to a decrease in both hardness and elastic modulus for all regions in the investigated samples. Investigations of thermomagnetic characteristics show the soft magnetic properties of the studied materials. More detailed studies of magnetisation versus magnetic field curves for the Fe79B20−xMxCu1 (where x = 0 or 4; M = Ti, Mo, Mn) alloy, recorded in a wide range of temperatures, followed by the law of approach to magnetic saturation revealed the relationship between microstructure and magneto-mechanical properties.

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