The Effect of Glass Chemistry on the Microstructub and Properties of Self Reinforced Silicon Nitride

1992 ◽  
Vol 287 ◽  
Author(s):  
Aleksander J. Pyzik ◽  
Daniel F. Carroll ◽  
C. James Hwang
Keyword(s):  
Silicon Nitride ◽  
Glass Matrix ◽  
Glassy Phase ◽  
Large Degree ◽  
Sufficient Condition ◽  
Flexure Strength ◽  
Maximum Flexure ◽  
The Matrix ◽  
Matrix Reinforcement

ABSTRACTThe advantage of self-reinforced silicon nitride is the in-situ control of the microstructure. This control is provided in large degree by the chemistry of glassy phase which can be adjusted to tailor the morphology of silicon nitride grains as well as the matrix - reinforcement interface. The presence of high aspect ratio silicon nitride grains is necessary but not sufficient condition to produce materials with optimum properties. For maximum flexure strength and fracture toughness an optimized glass matrix is required.

A Review on In Situ Synthesis of Al/TiC and Al/SiC-Composites

2016 ◽  
Vol 684 ◽  
pp. 287-292 ◽  
Author(s):  
Hrusikesh Nath
Keyword(s):  
Fine Particles ◽  
Matrix Composites ◽  
Homogeneous Microstructure ◽  
Large Particles ◽  
The Matrix ◽  
Matrix Reinforcement ◽  
Sic Composites ◽  
Al Matrix Composites ◽  
Al Matrix

The in-situ synthesis of ceramic particles in Al-matrix composites gives an uniform and homogeneous microstructure. The matrix reinforcement interface is compatible with the matrix, interface is clean and provides good interface bonding. The evenly distributed sub micron sized reinforcement particles in Al-matrix enhances the strength and toughness of the composite. The formation of particle clusters and agglomerations are minimized or eliminated by suitably choosing the in-situ process parameters. Large particles and agglomerate are easily fractured where as evenly distributed fine particles are resistant to crack propagation and improves the strength of the composites. The problem encountered with the formation of secondary intermetallic Al3Ti and Al4C3 phases are addressed.

Low Cost Si3N4/SiC Nanocomposites, Processing, RT and HT Properties

2006 ◽  
Vol 317-318 ◽  
pp. 185-190
Author(s):  
Pavol Šajgalík ◽  
Miroslav Hnatko ◽  
Zoltán Lenčéš ◽  
Ján Dusza ◽  
Monika Kašiarová ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Bending Strength ◽  
Low Cost ◽  
Creep Behaviour ◽  
Life Time ◽  
Mean Value ◽  
Sintering Process ◽  
The Matrix ◽  
Si3n4 Matrix

Silicon nitride - silicon carbide nanocomposite has been prepared by an in-situ method that utilizes formation of SiC nanograins by C+ SiO2 carbothermal reduction during the sintering process. The developed C/SiO2 derived nanocomposite consists of a silicon nitride matrix with an average Si3N4 matrix grain diameter of approximately 200 nm with inter- and intra- granular SiC inclusions with sizes of approximately 150 nm and 40 nm, respectively. The mean value of room temperature 4-point bending strength is 670 MPa with the Weibull modulus of 7.5 and indentation fracture toughness of 7.4 MPa.m1/2. The creep behaviour was investigated in bending at temperatures from 1200°C to 1450°C, under stresses ranking from 50 to 150 MPa in air. A significantly enhanced creep resistance was achieved by the incorporation of SiC nanoparticles into the matrix. The inserts machined from this composite have three times longer life time compared to those available on the market.

Preparation and Properties of Silicon-Corundum-Silicon Nitride Composites

2010 ◽  
Vol 150-151 ◽  
pp. 1294-1300
Author(s):  
Jun Cong Wei ◽  
Jun Bo Tu
Keyword(s):  
Silicon Nitride ◽  
Silicon Powder ◽  
Continuous Phase ◽  
Cold Strength ◽  
Hot Strength ◽  
Air Atmosphere ◽  
Industrial Experiments ◽  
The Matrix ◽  
Plastic Phase

Effects of silicon powder additions on the phase composition and microstructure of silicon- corundum-silicon nitride composite refractories were investigated guided by the theory of metal transient plastic phase and the Si-O-N phase diagram. On this basis, silicon-corundum-silicon nitride composites were prepared under air atmosphere. The results showed that the addition of silicon powder could reduce the width of the oxidized film and improve the densification; silicon addition could decrease the oxygen partial pressure in the specimens and contribute to the sintering of the materials. Part of silicon could remain in the materials. The industrial experiments suggested that silicon powder mostly filled in the interstices of the matrix of the sintered products with addition of less than 8 wt.% Si powder, and with increasing Si powder additions the densification of the product was improved, cold strength increased, and hot strength also increased due to the in-situ formed fibrous SIALON by silicon powder; silicon powder formed continuous phase which led to the decrease in densification and hot strength when more than 8 wt.% silicon powder was added.

MECHANICAL PROPERTIES OF IN-SITUFeAl-TiB2 INTERMETALLIC MATRIX COMPOSITES

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1479-1484 ◽  
Author(s):  
JONGHOON KIM ◽  
BONGGYU PARK ◽  
YONGHO PARK ◽  
IKMIN PARK ◽  
HEESOO LEE
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Matrix Composites ◽  
Intermetallic Matrix ◽  
Arc Melting ◽  
The Matrix ◽  
Matrix Reinforcement ◽  
Intermetallic Matrix Composites ◽  
Properties Of Composites

Intermetallic matrix composites reinforced with ceramic particles have received a great deal of attention. Iron aluminide is known to be a good material for the matrix in such composites. Two processes were used to fabricate FeAl - TiB 2 intermetallic matrix composites. One was liquid melt in-situ mixing, and the other was arc melting and suction casting processes. FeAl - TiB 2 IMCs obtained by two different methods were investigated to elucidate the influence of TiB 2 content. In both methods, the grain size in the FeAl alloy decreased with the presence of titanium diboride. The grain size of in-situ FeAl - TiB 2 IMCs became smaller than that of arc FeAl - TiB 2 IMCs. Significant increase in fracture stress and hardness was achieved in the composites. The in-situ process gives clean, contamination-free matrix/reinforcement interface which maintained good bonding causing high load bearing capability. This contributed to the increase in the mechanical properties of composites.

scholarly journals Supramolecular ionic polymer/carbon nanotube composite hydrogels with enhanced electromechanical performance

2020 ◽  
Vol 9 (1) ◽  
pp. 478-488 ◽  
Author(s):  
Yun-Fei Zhang ◽  
Fei-Peng Du ◽  
Ling Chen ◽  
Ka-Wai Yeung ◽  
Yuqing Dong ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Ion Mobility ◽  
Artificial Muscles ◽  
Ionic Polymer ◽  
Composite Hydrogels ◽  
The Matrix ◽  
Electromechanical Performance ◽  
Carbon Nanotube Composite ◽  
Robotic Devices

AbstractElectroactive hydrogels have received increasing attention due to the possibility of being used in biomimetics, such as for soft robotics and artificial muscles. However, the applications are hindered by the poor mechanical properties and slow response time. To address these issues, in this study, supramolecular ionic polymer–carbon nanotube (SIPC) composite hydrogels were fabricated via in situ free radical polymerization. The polymer matrix consisted of carbon nanotubes (CNTs), styrene sulfonic sodium (SSNa), β-cyclodextrin (β-CD)-grafted acrylamide, and ferrocene (Fc)-grafted acrylamide, with the incorporation of SSNa serving as the ionic source. On applying an external voltage, the ions accumulate on one side of the matrix, leading to localized swelling and bending of the structure. Therefore, a controllable and reversible actuation can be achieved by changing the applied voltage. The tensile strength of the SIPC was improved by over 300%, from 12 to 49 kPa, due to the reinforcement effect of the CNTs and the supramolecular host–guest interactions between the β-CD and Fc moieties. The inclusion of CNTs not only improved the tensile properties but also enhanced the ion mobility, which lead to a faster electromechanical response. The presented electro-responsive composite hydrogel shows a high potential for the development of robotic devices and soft smart components for sensing and actuating applications.

scholarly journals In situ structure and organization of the influenza C virus surface glycoprotein

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Steinar Halldorsson ◽  
Kasim Sader ◽  
Jack Turner ◽  
Lesley J. Calder ◽  
Peter B. Rosenthal
Keyword(s):  
Membrane Fusion ◽  
Hexagonal Lattice ◽  
Surface Glycoprotein ◽  
Structural Basis ◽  
Virus Surface ◽  
The Matrix ◽  
Influenza C Virus ◽  
Subtomogram Averaging ◽  
Electron Cryotomography

AbstractThe lipid-enveloped influenza C virus contains a single surface glycoprotein, the haemagglutinin-esterase-fusion (HEF) protein, that mediates receptor binding, receptor destruction, and membrane fusion at the low pH of the endosome. Here we apply electron cryotomography and subtomogram averaging to describe the structural basis for hexagonal lattice formation by HEF on the viral surface. The conformation of the glycoprotein in situ is distinct from the structure of the isolated trimeric ectodomain, showing that a splaying of the membrane distal domains is required to mediate contacts that form the lattice. The splaying of these domains is also coupled to changes in the structure of the stem region which is involved in membrane fusion, thereby linking HEF’s membrane fusion conformation with its assembly on the virus surface. The glycoprotein lattice can form independent of other virion components but we show a major role for the matrix layer in particle formation.

scholarly journals The Sorting of Mitochondrial DNA and Mitochondrial Proteins in Zygotes: Preferential Transmission of Mitochondrial DNA to the Medial Bud

1998 ◽  
Vol 142 (3) ◽  
pp. 613-623 ◽  
Author(s):  
Koji Okamoto ◽  
Philip S. Perlman ◽  
Ronald A. Butow
Keyword(s):  
Mitochondrial Dna ◽  
Fluorescent Protein ◽  
Yeast Cells ◽  
Mitochondrial Matrix ◽  
Outer Membranes ◽  
Marker Proteins ◽  
The Matrix ◽  
Green Fluorescent ◽  
Mitochondrial Reticulum

Green fluorescent protein (GFP) was used to tag proteins of the mitochondrial matrix, inner, and outer membranes to examine their sorting patterns relative to mtDNA in zygotes of synchronously mated yeast cells in ρ+ × ρ0 crosses. When transiently expressed in one of the haploid parents, each of the marker proteins distributes throughout the fused mitochondrial reticulum of the zygote before equilibration of mtDNA, although the membrane markers equilibrate slower than the matrix marker. A GFP-tagged form of Abf2p, a mtDNA binding protein required for faithful transmission of ρ+ mtDNA in vegetatively growing cells, colocalizes with mtDNA in situ. In zygotes of a ρ+ × ρ+ cross, in which there is little mixing of parental mtDNAs, Abf2p–GFP prelabeled in one parent rapidly equilibrates to most or all of the mtDNA, showing that the mtDNA compartment is accessible to exchange of proteins. In ρ+ × ρ0 crosses, mtDNA is preferentially transmitted to the medial diploid bud, whereas mitochondrial GFP marker proteins distribute throughout the zygote and the bud. In zygotes lacking Abf2p, mtDNA sorting is delayed and preferential sorting is reduced. These findings argue for the existence of a segregation apparatus that directs mtDNA to the emerging bud.

Sign in / Sign up

Export Citation Format

Share Document