Novel Shrinkage-Free Structural Ceramic Materials for Gas Turbine Applications

2008 ◽  
Author(s):  
A. V. Soudarev ◽  
V. G. Konakov ◽  
N. F. Morozov ◽  
I. A. Ovidko ◽  
B. N. Semenov
Keyword(s):  
Metal Cutting ◽  
Cutting Tools ◽  
Ceramic Materials ◽  
Diffusion Welding ◽  
Treatment Technique ◽  
The Novel ◽  
Sintering Process ◽  
Electrically Conductive ◽  
Sufficient Strength ◽  
Ceramic Blank

The paper presents results of development of the novel shrinkage-free, adaptable to machining and easily welded alumo-boron-carbide silicon materials that experience the cermet stage during their manufacturing. A specific feature of the like ceramics is their double-stage sintering process when, after the original stage, a metal-ceramic blank has a sufficient strength and is easily machined by conventional metal-cutting tools. In addition, such materials are electrically conductive, therefore, the elasto-erosion treatment technique can be applied. Subsequently, a machined part is finally sintered, whereas all the geometries remain actually unchanged due to the shrinkage absence. Prior to the final sintering, all separate parts can be joined by the diffusion welding with the seam strength being 5–10% different from the strength of the main part. The paper provides an insight into the processes and results of tests of the representative selections of samples of four types of the structural ceramics that are experiencing the cermet stage during the process of their formation. Also, ceramic parts for the CGTE hot passage are demonstrated.

scholarly journals Comparative tests of the metal cutting tools performance in the processing of stainless steels

2018 ◽  
Vol 441 ◽  
pp. 012052
Author(s):  
I V Shvetsov ◽  
B Ya Mokritskij ◽  
O A Malukhina ◽  
A H Rahmonov ◽  
V N Belyakov
Keyword(s):  
Stainless Steels ◽  
Metal Cutting ◽  
Cutting Tools ◽  
Comparative Tests

Steady-State Thermal Stresses in Wedge-Shaped Cutting Tools

1975 ◽  
Vol 97 (3) ◽  
pp. 1060-1066
Author(s):  
P. F. Thomason
Keyword(s):  
Thermal Stress ◽  
Steady State ◽  
Metal Cutting ◽  
Thermal Stresses ◽  
Heat Conduction Problem ◽  
Equivalent Stress ◽  
Cutting Tools ◽  
Thermoelastic Stress ◽  
Plastic State ◽  
Steady State Heat

Closed form expressions for the steady-state thermal stresses in a π/2 wedge, subject to constant-temperature heat sources on the rake and flank contact segments, are obtained from a conformal mapping solution to the steady-state heat conduction problem. It is shown, following a theorem of Muskhelishvili, that the only nonzero thermal stress in the plane-strain wedge is that acting normal to the wedge plane. The thermal stress solutions are superimposed on a previously published isothermal cutting-load solution, to give the complete thermoelastic stress distribution at the wedge surfaces. The thermoelastic stresses are then used to determine the distribution of the equivalent stress, and this gives an indication of the regions on a cutting tool which are likely to be in the plastic state. The results are discussed in relation to the problems of flank wear and rakeface crater wear in metal cutting tools.

Hard Nano-Crystalline Coatings for Cutting Tools

2007 ◽  
Vol 567-568 ◽  
pp. 185-188 ◽  
Author(s):  
Miroslav Piska
Keyword(s):  
High Speed ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Dry Cutting ◽  
Nano Crystalline ◽  
The Right ◽  
Machining Productivity ◽  
Hard Cutting ◽  
Cutting Tool Materials

Modern trends in metal cutting, high speed/feed machining, dry cutting and hard cutting set more demanding characteristics for cutting tool materials. The exposed parts of the cutting edges must be protected against the severe loading conditions and wear. The most significant coatings methods for cutting tools are PVD and CVD/MTCVD today. The choice of the right substrate or the right protective coating in the specific machining operation can have serious impact on machining productivity and economy. In many cases the deposition of the cutting tool with a hard coating increases considerably its cutting performance and tool life. The coating protects the tool against abrasion, adhesion, diffusion, formation of comb cracks and other wear phenomena.

Nanostructural wear-resistant coatings produced on metal-cutting tools by electric-arc evaporation and magnetronic sputtering

2010 ◽  
Vol 30 (9) ◽  
pp. 910-920 ◽  
Author(s):  
F. V. Kiryukhantsev-Korneev ◽  
N. A. Shirmanov ◽  
A. N. Sheveiko ◽  
E. A. Levashov ◽  
M. I. Petrzhik ◽  
...  
Keyword(s):  
Metal Cutting ◽  
Cutting Tools ◽  
Electric Arc ◽  
Wear Resistant ◽  
Wear Resistant Coatings ◽  
Arc Evaporation

scholarly journals Role of Sintering Temperature in Production of Nepheline Ceramics-Based Geopolymer with Addition of Ultra-High Molecular Weight Polyethylene

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1077
Author(s):  
Romisuhani Ahmad ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Wan Mastura Wan Ibrahim ◽  
Kamarudin Hussin ◽  
Fakhryna Hannanee Ahmad Zaidi ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Sintering Temperature ◽  
Ceramic Materials ◽  
Microstructural Properties ◽  
Sintering Process ◽  
Final Microstructure ◽  
Change Of Microstructure ◽  
Ultra High Molecular Weight

The primary motivation of developing ceramic materials using geopolymer method is to minimize the reliance on high sintering temperatures. The ultra-high molecular weight polyethylene (UHMWPE) was added as binder and reinforces the nepheline ceramics based geopolymer. The samples were sintered at 900 °C, 1000 °C, 1100 °C, and 1200 °C to elucidate the influence of sintering on the physical and microstructural properties. The results indicated that a maximum flexural strength of 92 MPa is attainable once the samples are used to be sintered at 1200 °C. It was also determined that the density, porosity, volumetric shrinkage, and water absorption of the samples also affected by the sintering due to the change of microstructure and crystallinity. The IR spectra reveal that the band at around 1400 cm−1 becomes weak, indicating that sodium carbonate decomposed and began to react with the silica and alumina released from gels to form nepheline phases. The sintering process influence in the development of the final microstructure thus improving the properties of the ceramic materials.

Forecasting Performance of Ceramic Cutting Tool

2017 ◽  
Vol 736 ◽  
pp. 86-90 ◽  
Author(s):  
Vyacheslav Maksarov ◽  
A. Khalimonenko
Keyword(s):  
Electrical Resistance ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Tool Material ◽  
Ceramic Materials ◽  
Specific Electrical Resistance ◽  
Testing Methods ◽  
Microstructural Parameters ◽  
Forecasting Performance ◽  
Nondestructive Testing Methods

The article considers the problems of forecasting the performance of cutting tools equipped with replaceable ceramic cutting bits. It is proposed to forecast the operability of ceramic tools on the ground of dependence between its performance characteristics and the microstructural parameters of the tool material. It is proposed to determine the parameters of ceramic bits microstructure by a nondestructive testing methods based on measuring the specific electrical resistance of ceramic materials. As a result of the study we have undertaken, a relationship was detected between the performance and specific electrical resistance of ceramic cutting tools.

scholarly journals Clinical Efficacy of Scalene Injection for Thoracic Outlet Syndrome

2021 ◽  
Author(s):  
Samuel Baek ◽  
Seok Kim ◽  
Myung Ho Shin ◽  
Tae Min Kim ◽  
Seoung-Joon Lee ◽  
...  
Keyword(s):  
Side Effects ◽  
Clinical Efficacy ◽  
Rating Scale ◽  
Numerical Rating Scale ◽  
Neck Disability Index ◽  
Vital Signs ◽  
Treatment Technique ◽  
The Novel ◽  
Numerical Rating ◽  
Neck Disability

Purpose: We introduce the novel treatment technique, scalene injection, and study its clinical efficacy for diagnosis, treatment, and pain control for patients with thoracic outlet syndrome.Methods: Between November 2001 and October 2018, 266 patients were studied retrospectively. To evaluate the efficacy and sustainability, we checked the numerical rating scale (NRS) for pain relief and neck disability index (NDI) for functional improvements, prior to and 1, 12 weeks after the injection. The safety was evaluated by examining side effects for at least 24 hours from the point of injection.Results: NRS was improved from 7.12 to 3.11 at 1 week, and to 3.05 at 12 weeks (p<0.05). NDI was improved from 15.87 to 6.15 at 1 week, and to 6.19 at 12 weeks (p<0.05). There were two cases of convulsion immediately after the injection and were treated with prompt oxygen supply and sedatives. Transient side effects included two cases of dyspnea and one case of nausea and were resolved within 1 hour after. All five cases showed symptoms of side effects on the day of injection and were resolved within a day. A total of 242 patients (91.0%) experienced immediate declines in NRS and 161 patients experienced persistent declines for more than 12 weeks. However, 24 patients (9.0%) showed no improvement and 20 patients (7.5%) experienced increases in NRS.Conclusion: Scalene injection is also effective as a therapeutic method. However, this study suggests that it must be done with monitoring of vital signs in an operating room for any possible complications and side effects.

scholarly journals Vibration-based tool life monitoring for ceramics micro-cutting under various toolpath strategies

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 125
Author(s):  
Zsolt János Viharos ◽  
László Móricz ◽  
Máté István Büki
Keyword(s):  
Tool Path ◽  
High Efficiency ◽  
Vibration Signal ◽  
Ceramic Materials ◽  
Micro Milling ◽  
The Novel ◽  
Feature Selection Technique ◽  
Tool Condition ◽  
Signal Features ◽  
Milling Tool

The 21st century manufacturing technology is unimagined without the various CAM (Computer Aided Manufacturing) toolpath generation programs. The aims of developing the toolpath strategies which are offered by the cutting control software is to ensure the longest possible tool lifetime and high efficiency of the cutting method. In this paper, the goal is to compare the efficiency of the 3 types of tool path strategies in the very special field of micro-milling of ceramic materials. The dimensional distortion of the manufactured geometries served to draw the Taylor curve for describing the wearing progress of the cutting tool helping to determine the worn-in, normal and wear out stages. These isolations allow to separate the connected high-frequency vibration measurements as well. Applying the novel feature selection technique of the authors, the basis for the vibration based micro-milling tool condition monitoring for ceramics cutting is presented for different toolpath strategies. It resulted in the identification of the most relevant vibration signal features and the presentation of the identified and automatically separated tool wearing stages as well.

Development of High Performance Silicon Nitride Ceramics and their Applications

1992 ◽  
Vol 287 ◽  
Author(s):  
Yo Tajima
Keyword(s):  
Mechanical Properties ◽  
Silicon Nitride ◽  
High Performance ◽  
Future Prospect ◽  
Cutting Tools ◽  
Sintering Process ◽  
Sintering Additives ◽  
Nitride Ceramics ◽  
Engine Components

ABSTRACTProgress in sintering process and improvement of mechanical properties of silicon nitride ceramics are reviewed. Emphases are placed on contributions of advanced sintering techniques and better understanding of sintering additives and microstructure-properties relations. Current applications as engine components and cutting tools are described, and future prospect is considered.

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