Preparation of In Situ Synthesized SiC Particles Reinforced Highly Porous Si3N4 Ceramics by Gel-Casting

2008 ◽  
Vol 368-372 ◽  
pp. 898-900
Author(s):  
Hong Zeng ◽  
Hong Jie Wang ◽  
Juan Li Yu ◽  
Dan Bo Lin ◽  
Guan Jun Qiao ◽  
...  
Keyword(s):  
High Strength ◽  
Xrd Analysis ◽  
High Porosity ◽  
Water Displacement ◽  
Contributing Factors ◽  
Homogeneous Microstructure ◽  
Three Point Bending ◽  
Gel Casting ◽  
Sic Particles ◽  
Highly Porous

In this paper, highly porous Si3N4 ceramics with high strength, homogeneous microstructure were fabricated by introducing a proper amount of nanometer carbon in the Si3N4 slurry by gel-casting. Scanning electron microscopy, X-ray diffraction, Archimedes water-displacement method and three-point bending tests were employed to analyze the microstructures and mechanical properties of the sintered bodies. It was shown by the XRD analysis that SiC particles were formed in the sintered bodies. The pillar β- Si3N4 morphology, homogeneous microstructure and the SiC particles as a reinforcement phase are the contributing factors for high porosity and good mechanical behavior.

Influence of Fabricated Process on Mechanical Properties of Porous SiC-Particle/Si3N4 Composites

2007 ◽  
Vol 336-338 ◽  
pp. 1320-1323 ◽  
Author(s):  
Hong Jie Wang ◽  
Wen Zhang ◽  
Yu Bai ◽  
Guan Jun Qiao ◽  
Ji Qiang Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Powder Compact ◽  
High Strength ◽  
Uniform Structure ◽  
High Porosity ◽  
Gel Casting ◽  
N2 Atmosphere ◽  
Porous Sic ◽  
Sic Particle

In this paper, the mechanical properties of porous Si3N4/SiC composite prepared by different forming method (uniaxial pressing and gel-casting) were compared. Using gelcasting and two steps sintering technology, the porous SiC-particle/Si3N4 composites with a high strength, uniform structure and a relative high porosity were obtained by adding a little amount of nano carbon in slurry. The flexural strength of optimized material reaches to 100MPa and its porosity is more than 60%. But using uniaxial pressing and sintering at N2 atmosphere, because the green bodies have the high density, and the density distribution of a powder compact was not uniform, the flexural strength is not high, and at the same time, the microstructure is not uniform also.

Preparation of In Situ Synthesized SiC Particles Reinforced Highly Porous Si3N4 Ceramics by Gel-Casting

2008 ◽  
pp. 898-900
Author(s):  
Hong Zeng ◽  
Hong Jie Wang ◽  
Juan Li Yu ◽  
Dan Bo Lin ◽  
Guan Jun Qiao ◽  
...  
Keyword(s):  
Porous Si ◽  
Gel Casting ◽  
Sic Particles ◽  
Highly Porous

Experimental Study on Fracture Toughness of Q460C the High-Strength Construction Steel at Low Temperature

2011 ◽  
Vol 71-78 ◽  
pp. 890-897 ◽  
Author(s):  
Yuan Qing Wang ◽  
Yun Lin ◽  
Yan Nian Zhang ◽  
Yong Jiu Shi
Keyword(s):  
Low Temperature ◽  
High Strength ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Three Point Bending ◽  
Function Fitting ◽  
Ductile Brittle Transition Temperature ◽  
Boltzmann Function ◽  
Fracture Appearance ◽  
Crack Tip Opening

Three point bending tests were carried out on 14mm-thick Q460C the high-strength structural steel at low temperature, and scanning electronic microscope of the fracture appearance was analyzed. The results showed that the obvious feature of brittle mechanism was shown on the three point bending specimen fracture whose testing took place at -40°C. And the crack tip opening displacement value of Q460C steel, which was less than that of Q235 steel, Q345 steel and Q390 steel at low temperature, tended to decrease with respect to the temperature reduction. Moreover, a Boltzmann function fitting analysis was applied to the experimental data, and the ductile-brittle transition temperature and the changing regularity were obtained.

Microstructure Evolution and Deformation Mechanisms of Harmonic Structure Designed Materials

2016 ◽  
Vol 879 ◽  
pp. 145-150
Author(s):  
Kei Ameyama ◽  
Sanjay Kumar Vajpai ◽  
Mie Ota
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Powder Metallurgy ◽  
Early Stage ◽  
High Strength ◽  
Plastic Instability ◽  
Structure Design ◽  
Harmonic Structure ◽  
Homogeneous Microstructure ◽  
Macro Scale

This paper presents the novel microstructure design, called Harmonic Structure, which gives structural metallic materials outstanding mechanical properties through an innovative powder metallurgy process. Homogeneous and ultra-fine grain (UFG) structure enables the materials high strength. However, such a “Homo-“ and “UFG” microstructure does not, usually, satisfy the need to be both strong and ductile, due to the plastic instability in the early stage of the deformation. As opposed to such a “Homo-and UFG“ microstructure, “Harmonic Structure” has a heterogeneous microstructure consisting of bimodal grain size together with a controlled and specific topological distribution of fine and coarse grains. In other words, the harmonic structure is heterogeneous on micro-but homogeneous on macro-scales. In the present work, the harmonic structure design has been applied to pure metals and alloys via a powder metallurgy route consisting of controlled severe plastic deformation of the corresponding powders by mechanical milling or high pressure gas milling, and subsequent consolidation by SPS. At a macro-scale, the harmonic structure materials exhibited superior combination of strength and ductility as compared to their homogeneous microstructure counterparts. This behavior was essentially related to the ability of the harmonic structure to promote the uniform distribution of strain during plastic deformation, leading to improved mechanical properties by avoiding or delaying localized plastic instability.

Investigation of Mechanical Properties of Nano Sized Clay/LDH Particle as Hybrid Nano Composite Material

2015 ◽  
Vol 766-767 ◽  
pp. 355-361
Author(s):  
S. Sivasaravanan ◽  
V.K. Bupesh Raja ◽  
S. Prabhu ◽  
S. Dineshkumar ◽  
Gokulaprasad
Keyword(s):  
Composite Material ◽  
Testing Machine ◽  
Weight Ratio ◽  
High Strength ◽  
Sem Analysis ◽  
Bending Test ◽  
Flexural Property ◽  
Weight Percentage ◽  
Three Point Bending ◽  
Sonication Technique

Usage of Hybrid nanocomposite materials provides a greater opportunity to replace the conventional materials due to their properties such as light weight and high strength to based on weight ratio. In this synergitic study, nanosized clay particle and layered double hydroxide particles are used. nanoclay and LDH particles were mixed on the bases of weight percentage (1wt% to 5wt%) by ultra sonication technique. The composite material was fabricated by one of the most common method known as hand lay-up technique. The composite materials was prepared in the form of plate with 4mm of thickness.The characterization of tensile and flexural property of the nanoclay, LDH and combination of both was analysis by tensile test using universal testing machine and three point bending test respectively. The tensile and three point bending test specimens were cut to size as per ASTM standard.The morphology of composite was studied using SEM analysis.

An Experimental Evaluation of Energy Absorption of TRIP Steel by Small Punch Test

2016 ◽  
Vol 725 ◽  
pp. 60-65
Author(s):  
Asuka Hayashi ◽  
Takeshi Iwamoto
Keyword(s):  
Energy Absorption ◽  
Trip Steel ◽  
Dynamic Condition ◽  
High Strength ◽  
High Energy ◽  
Bending Test ◽  
Absorption Characteristic ◽  
Small Punch ◽  
Three Point Bending ◽  
Punch Test

TRIP steel possesses high strength and excellent ductility. In addition, it is possible that TRIP steel indicates high energy absorption so that TRIP steel is expected to apply to automotive members. To design the members made of TRIP steel, it is important to clarify its energy absorption characteristic at various deformation rates. In the previous study, the energy absorption characteristic of TRIP steel is evaluated by J-integral under quasi-static to dynamic condition by using a thick specimen based on ASTM standard. However, by using such thick specimens, it is difficult to conduct the three-point bending test under impact condition because of high ductility in TRIP steel. A small punch (SP) test is the experimental method which can evaluate fracture parameters such as J-integral. By using a conventional use of small specimen in the SP test, it is possible to evaluate J-integral of TRIP steel under impact deformation. In this study, energy absorption characteristic of TRIP steel is investigated by SP test under different deflection rates. Then, the relationship between the values of J-integral obtained by previously conducted three-point bending test and the SP test of TRIP steel is discussed.

Synthesis of Nanoporous Material from Lignin via Carbonization Assisted Acid Activation

2020 ◽  
Vol 990 ◽  
pp. 149-154
Author(s):  
Nutchaporn Ngamthanacom ◽  
Napat Kaewtrakulchai ◽  
Weerawut Chaiwat ◽  
Laemthong Chuenchom ◽  
Masayoshi Fuji ◽  
...  
Keyword(s):  
Pulp Mill ◽  
Total Pore Volume ◽  
Nanoporous Carbon ◽  
Carbonization Temperature ◽  
Acid Activation ◽  
High Porosity ◽  
Process Variables ◽  
X Ray Diffraction ◽  
X Ray ◽  
Highly Porous

Waste lignin (WL) from the pulp mill and paper was studied for its potential application to prepare the nanoporous carbon with high porosity via carbonization assisted acid activation. The effect of acid activation such as HNO3, HCl, H2SO4, and H3PO4 on lignin transformation to nanoporous carbon investigated. The physicochemical properties of nanoporous carbon were comprehensively characterized through N2 sorption, Scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR), respectively. N2 sorption revealed that the condition using 5% vol of phosphoric acid activation at carbonization temperature of 700°C for 2 h exhibited the highly porous structure of carbon nanoparticles with a total pore volume of 0.035 cm3/g. With the properly selecting process variables of waste lignin development could be producing high porosity nanoporous carbon.

scholarly journals Effect of Intercritical Annealing and Austempering on the Microstructure and Mechanical Properties of a High Silicon Manganese Steel

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1448 ◽  
Author(s):  
Mattia Franceschi ◽  
Luca Pezzato ◽  
Claudio Gennari ◽  
Alberto Fabrizi ◽  
Marina Polyakova ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Intercritical Annealing ◽  
High Strength ◽  
Xrd Analysis ◽  
Tensile Tests ◽  
Manganese Steel ◽  
Microstructure And Mechanical Properties ◽  
Martensitic Microstructure ◽  
Steel Grades ◽  
High Silicon

High Silicon Austempered steels (AHSS) are materials of great interest due to their excellent combination of high strength, ductility, toughness, and limited costs. These steel grades are characterized by a microstructure consisting of ferrite and bainite, accompanied by a high quantity retained austenite (RA). The aim of this study is to analyze the effect of an innovative heat treatment, consisting of intercritical annealing at 780 °C and austempering at 400 °C for 30 min, on the microstructure and mechanical properties of a novel high silicon steel (0.43C-3.26Si-2.72Mn wt.%). The microstructure was characterized by optical and electron microscopy and XRD analysis. Hardness and tensile tests were performed. A multiphase ferritic-martensitic microstructure was obtained. A hardness of 426 HV and a tensile strength of 1650 MPa were measured, with an elongation of 4.5%. The results were compared with those ones obtained with annealing and Q&T treatments.

The Chemical Reactivity Comparison of High-Modulus and High-Strength Carbon Fibers

2020 ◽  
Vol 989 ◽  
pp. 347-352
Author(s):  
A.I. Gomzin ◽  
R.F. Gallyamova ◽  
N.G. Zaripov ◽  
S.N. Galyshev ◽  
F.F. Musin
Keyword(s):  
Carbon Fibers ◽  
Chemical Reactivity ◽  
High Strength ◽  
Mechanical Tests ◽  
High Modulus ◽  
Initial State ◽  
Alloy Matrix ◽  
Three Point Bending ◽  
Burn Out ◽  
High Strength Fiber

In this study two types of PAN-based continuous carbon fibers were compared: high-modulus UMT-430 and high-strength UMT-49. The dynamics of carbon fibers oxidation at a temperature of 600°C with an exposure from 1 to 6 hours was evaluated. It was found that high-strength fibers burn out faster than high-modulus. The surface of the fibers in the initial state and after annealing was investigated. Composite samples with an Al-6Mg alloy matrix, reinforced with these types of carbon fibers, were tested for three-point bending. It was found that the strength of the composite with high-modulus fiber was more than 2 times higher than strength of the composite with high-strength fiber. The samples fracture surfaces of Cf/Al composites after mechanical tests are investigated.

Hot Forming Technique and Its Equipments for Ultra High Strength Steel

2010 ◽  
Author(s):  
Ning Ma ◽  
Ping Hu
Keyword(s):  
High Strength Steel ◽  
Chemical Engineering ◽  
Cooling System ◽  
High Strength ◽  
Hot Forming ◽  
Continuous Heating ◽  
Step Method ◽  
Three Point Bending ◽  
Ultra High Strength Steel ◽  
One Step

Hot forming of ultra high strength steel is an advanced forming technique which can not only represent the best solution to increasing the strength-to-mass ratio of sheet components, but also meet the need of higher passive safety and weight reduction. Based on independently developed mass production line of hot forming, its key forming and quenching technique and relative equipments are proposed and described, including multi-step and one-step method, die manufacturing with cooling system, continuous heating furnace and integrated manufacturing system composed of the advanced interdisciplinary technology of machining, electronic control, material and chemical engineering. Then the automobile body components are produced by the developed equipments of hot forming and moreover their mechanical properties are investigated. The typical tensile curve of the quenched components shows that the yield stress of the hot forming component is over 1000MPa, and the strength limitation is over 1600MPa. The three-point bending testing of the part is implemented. These experimental results indicate the validity of the developed technique and equipments.

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