A Microstructural Study of Hot Pressed and Reactive Sintered Beta-Silicon Nitride Coated with Alumina

1997 ◽  
Vol 3 (S2) ◽  
pp. 735-736
Author(s):  
G. Ghosh ◽  
S. Vaynman ◽  
M. E. Fine
Keyword(s):  
Silicon Nitride ◽  
Glassy Phase ◽  
Phase Particle ◽  
High Strength ◽  
High Fracture Toughness ◽  
Boundary Phase ◽  
High Fracture ◽  
Engineering Applications ◽  
Particle Coating ◽  
Blending Method

Silicon nitride-based or SiAlON ceramics are increasingly being considered for many engineering applications due to their low density, high strength, and high modulus. For many engineering applications SiAlON ceramics are required to have, among many other properties, both high fracture toughness and good tribological properties. Typically, an interlocking microstructure consisted of β-Si3N4 and/or β'-SiAlON grains is produced, by sintering Si3N4 with desirable additive(s), with a residual glassy or partly crystalline grain boundary phase. The fracture process in such a microstructure is predominantly intergranular, the cracks tend to follow a tortuous path. However, the presence of an intergranular glassy phase causes rapid deterioration of properties at temperature above the glass transition temperature. Therefore, in order to improve high-temperature properties of these ceramics it is desirable to minimize, and if possible to eliminate, the intergranular glassy phase. Particle coating techniques are receiving increasing attention as they are convenient ways of incorporating sintering aids/dopants more uniformly than conventional powder blending method.

Mechanical Properties of Si3N4 Ceramics Prepared by Nitrided Pressureless Sintered (NPS) Process

2007 ◽  
Vol 124-126 ◽  
pp. 1461-1464
Author(s):  
Chang Gyu Kang ◽  
Joong Gwun Park ◽  
Tae Won Kang ◽  
Chul Kim ◽  
Tae Woo Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Silicon Nitride ◽  
Molten Aluminum ◽  
Continuous Process ◽  
High Hardness ◽  
High Strength ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Silicon Nitride Ceramic ◽  
Ceramic Components

As an alternative to degassing pipe and rotor blade using in molten aluminum industry, we investigate the mechanical properties of silicon nitride ceramic components prepared by nitrided pressureless sintered (NPS) process, which process is the continuous process of nitridation reaction process combined with pressureless sintering. Mechanical properties of silicon nitride prepared by NPS process with sintering additives of 5wt% Y2O3, 5wt% Al2O3 and 20wt% Si show high strength, >500 MPa, high hardness, 12.6 GPa, and superior damage tolerances with high fracture toughness, 9.8 MPam1/2.

Z-201N

Alloy Digest ◽  
1991 ◽  
Vol 40 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
Silicon Nitride ◽  
Room Temperature ◽  
High Strength ◽  
High Fracture Toughness ◽  
Bend Strength ◽  
High Fracture ◽  
Engineering Ceramic ◽  
Room Temperature Strength

Abstract Z-201N is a high strength zirconia engineering ceramic. Its room temperature strength is greater than that of silicon carbide and silicon nitride. It also has high fracture toughness. This datasheet provides information on composition, physical properties, hardness, elasticity, and bend strength as well as fracture toughness. Filing Code: Cer-6. Producer or source: Kyocera Industrial Ceramics Corporation.

FERRIUM M54

Alloy Digest ◽  
2018 ◽  
Vol 67 (9) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
High Resistance ◽  
High Strength ◽  
Cost Effective ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Structural Applications ◽  
Resistance To Stress

Abstract Ferrium M54 was designed to create a cost-effective, ultra high-strength, high-fracture toughness material with a high resistance to stress-corrosion cracking for use in structural applications. This datasheet provides information on composition, hardness, and tensile properties as well asfatigue. Filing Code: SA-822. Producer or source: QuesTek Innovations, LLC.

scholarly journals Investigation into the Structural, Chemical and High Mechanical Reforms in B4C with Graphene Composite Material Substitution for Potential Shielding Frame Applications

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1921
Author(s):  
Ibrahim M. Alarifi
Keyword(s):  
Composite Material ◽  
Melting Point ◽  
Boron Carbide ◽  
High Strength ◽  
Stir Casting ◽  
High Fracture Toughness ◽  
Chemical Compositions ◽  
High Fracture ◽  
Fabrication Procedure ◽  
Standard Designs

In this work, boron carbide and graphene nanoparticle composite material (B4C–G) was investigated using an experimental approach. The composite material prepared with the two-step stir casting method showed significant hardness and high melting point attributes. Scanning electron microscopy (SEM), along with energy dispersive X-ray spectroscopy (EDS) analysis, indicated 83.65%, 17.32%, and 97.00% of boron carbide + 0% graphene nanoparticles chemical compositions for the C-atom, Al-atom, and B4C in the compound studied, respectively. The physical properties of all samples’ B4C–G like density and melting point were 2.4 g/cm3 density and 2450 °C, respectively, while the grain size of B4C–G was in the range of 0.8 ± 0.2 µm. XRD, FTIR, and Raman spectroscopic analysis was also performed to investigate the chemical compositions of the B4C–G composite. The molding press composite machine was a fabrication procedure that resulted in the formation of outstanding materials by utilizing the sintering process, including heating and pressing the materials. For mechanical properties, high fracture toughness and tensile strength of B4C–G composites were analyzed according to ASTM standard designs. The detailed analysis has shown that with 6% graphene content in B4C, the composite material portrays a high strength of 134 MPa and outstanding hardness properties. Based on these findings, it is suggested that the composite materials studied exhibit novel features suitable for use in the application of shielding frames.

Research on Titanium Alloys with High Toughness and High Damage Tolerance

2009 ◽  
Vol 618-619 ◽  
pp. 97-100
Author(s):  
Yong Qing Zhao ◽  
Heng Lei Qu ◽  
Jun Chen
Keyword(s):  
Damage Tolerance ◽  
Rapid Development ◽  
Crack Propagation Rate ◽  
High Strength ◽  
High Fracture Toughness ◽  
Ti Alloy ◽  
Chinese Market ◽  
High Fracture ◽  
High Toughness ◽  
Ti Alloys

The recent shift in the design focus for aeroplanes from strength to damage tolerance has led to a subsequent shift in the focus of Ti alloy research. China first started to research Ti alloys with damage tolerance from the year 2000. The first product stemming from this research is a Ti alloy with high strength, high toughness and damage tolerance (TC21). TC21 exhibits high strength (UTS  1100MPa), high fracture toughness (K1c  70MPa.m1/2) and a low crack propagation rate (da/dN being similar to Ti-6-4 with  annealing). Another Ti alloy, named TC4-DT, has also been produced. It has moderate strength, along with high toughness and damage tolerance (UTS  900MPa, K1c  70MPa.m1/2, da/dN being similar to Ti-6-4 with  annealing). Both TC21 and TC4-DT are now undergoing rapid development, with the former alloy also being applied to a full scale aeronautical application. Both TC21 and TC4-DT have promising futures in the industry. They will be the main Ti alloys with damage tolerance utilised in the Chinese market.

Plasma Arc Spraying of Cu-Ti-Zr-Ni Amorphous Alloys

2000 ◽  
Author(s):  
D.J. Sordelet ◽  
P. Huang ◽  
M.F. Besser ◽  
E. Lepecheva
Keyword(s):  
Cross Sections ◽  
Metallic Glasses ◽  
High Strength ◽  
Amorphous Structure ◽  
High Fracture Toughness ◽  
Arc Spraying ◽  
Plasma Arc ◽  
High Fracture ◽  
Spray Coatings ◽  
Sprayed Coatings

Abstract A brief feasibility study was performed to produce thermal spray coatings using gas atomized powders of Cu47Ti34-xZr11Ni8Six, where x=0 and 1. These alloys have previously been shown to be capable of forming metallic glasses having thick (1-2 cm) cross sections because they can be cooled from the melt at relatively low cooling rates (e.g., 100-102Ks-1). The properties of these metallic glasses include high strength, high elasticity and high fracture toughness. Amorphous plasma arc sprayed coatings were produced which were close in composition to the starting powders, and exhibited comparable glass transition and crystallization behavior. The amorphous structure of the as-sprayed coatings was used as a source for forming a range of partially devitrified and fully crystallized structures. The average hardness of the coatings increased from around 6 GPa to near 10 GPa as the degree of crystallization increased.

Ceramic Gas Turbine Development: Need for a 10-Year Plan

2008 ◽  
Author(s):  
Mark van Roode
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Large Scale ◽  
Energy Savings ◽  
High Strength ◽  
Combined Cycle ◽  
High Fracture Toughness ◽  
Development Programs ◽  
High Fracture ◽  
Electrical Efficiency

Ceramic gas turbine development that started in the 1950s has slowed considerably since most of the large-scale ceramic gas turbine development programs of the 1970s–1990s ended. While component durability still does not meet expectations, the prospect of significant energy savings and emissions reductions, potentially achievable with ceramic gas turbines, continues to justify development efforts. Four gas turbine applications have been identified that could be commercially attractive: a small recuperated gas turbine (microturbine) with ∼35% electrical efficiency, a recuperated gas turbine for transportation applications with ∼40% electrical efficiency with potential applications for efficient small engine cogeneration, a ∼40% efficient mid-size industrial gas turbine and a ∼63% (combined cycle) efficient utility turbine. Key technologies have been identified to ensure performance and component durability targets can be met over the expected life cycle for these applications. These technologies include: a Si3N4 or SiC with high fracture toughness, durable EBCs for Si3N4 and SiC, an effective EBC/TBC for SiC/SiC, a durable Oxide/Oxide CMC with thermally insulating coating, and the Next Generation CMCs with high strength that can be used as structural materials for turbine components for small engines and for rotating components in engines of various sizes. The programs will require integrated partnerships between government, national laboratories, universities and industry. The overall cost of the proposed development programs is estimated at U.S. $100M over ten-years, i.e. an annual average of U.S. $10M.

Preparation and Characterization of Reaction Sintering B4C/SiC Composite Ceramic

2014 ◽  
Vol 602-603 ◽  
pp. 536-539
Author(s):  
Hai Bin Sun ◽  
Yu Jun Zhang ◽  
Qi Song Li
Keyword(s):  
Fracture Toughness ◽  
High Performance ◽  
Bending Strength ◽  
Carbon Sources ◽  
High Hardness ◽  
High Strength ◽  
Composite Ceramic ◽  
High Fracture Toughness ◽  
Reaction Sintering ◽  
High Fracture

High hardness, high strength, high fracture toughness and low density are required for novel bulletproof materials. B4C/SiC composite ceramic is one of the most potential candidates. In this study, B4C/SiC composite ceramic was prepared by reaction sintering. The influence of B4C content, species and content of carbon, sintering temperature on the mechanical properties of B4C/SiC composite ceramic were studied. A high performance B4C/SiC composite ceramic was sintered at 1750°C for 30 min. Phenolic resin and carbon black were both chosen as carbon sources, whose favorable contents were 10wt%, 5wt%, respectively. The density of sintered bodies reduces with B4C content increases. To some extent, fracture toughness, bending strength improve initially and then deteriorate with the increase of B4C content whose optimal amount is 30wt%. The optimal fracture toughness and bending strength of the B4C/SiC composite ceramic are 5.07MPa·m1/2 and 487MPa, respectively. Meanwhile, the Viker-hardness of the sintered body is 30.2GPa, the density is as low as 2.82g/cm3.

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