scholarly journals Influence of diamond component based on wurtzite boron nitride on wear resistance of cutting tool

2020 ◽  
Vol 6 (2) ◽  
pp. 53-60
Author(s):  
Volodymyr Volkogon ◽  
◽  
Svitlana Avramchuk ◽  
Yuriy Fedoran ◽  
Andrii Kravchuk ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Heat Dissipation ◽  
Superhard Material ◽  
Cutting Tool ◽  
Decisive Role ◽  
Hardened Steels ◽  
Processed Material ◽  
The Matrix ◽  
The Coefficient Of Friction ◽  
The Stability

The article is devoted to the study of the influence of the diamond component in a composite superhard material based on wurtzite boron nitride on the stability of the tool during turning of hardened steels in the mode of smooth turning and when processing intermittent surfaces. The aim of the work is to study the influence of the content of the diamond component in the composite superhard material based on wurtzite boron nitride on the stability of the tool. Based on the analysis of the main patterns of changes in the coefficient of friction depending on various factors, the evaluation of composites containing diamonds of different dispersion in comparison with other materials of this class. The results of the study of the technical level of composite polycrystalline superhard materials based on wurtzite boron nitride of different composition and determination of the efficiency of their use as a cutting tool in the machining of hardened steels are presented. The intensity of wear of composites in the cutting tool during processing of hardened steels is experimentally determined. It is established that the presence of a diamond component in the composite significantly affects the stability of the tool in the conditions of smooth turning due to heat dissipation in contact with the processed material. In the processing of hardened steels with the presence of shock loads, the phase state of the matrix component of the composite plays a decisive role. The obtained research results make it possible to determine the optimal composition and conditions for obtaining a composite material of the system “boron nitride – diamond”, which provides the most effective application of the cutting tool in practice.

Tool Coatings with the Effect of Adaptation to Cutting Conditions

2011 ◽  
Vol 496 ◽  
pp. 75-79 ◽  
Author(s):  
Mars Migranov ◽  
Regina Migranov
Keyword(s):  
High Speed ◽  
Heat Dissipation ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Chip Thickness ◽  
Shear Plane ◽  
Wear Resistant Coatings ◽  
Tool Coatings ◽  
The Coefficient Of Friction ◽  
Tribological Parameters

The objective of the present work is to study tribological properties of multilayered wear resistant coatings on the cutting tools. Two types of coatings (TiAl)N were studied: normal monolayer coating and improved coating. The tests were conducted with cooling, and without it. During high speed machining an intensive tribo-oxidation of tool surface occurs. Formation of aluminum oxide films on the surface of cutting tool significantly changes the heat flow and heat dissipation into the chip. Conditions of the chips formation (chip thickness ratio and the shear plane angle) and the coefficient of friction on the rake face of the cutting tool have been measured during the cutting process. The results demonstrated significant improvement of tribological parameters for the cutting tools with filtered coatings.

Thermal and dielectric properties of epoxy-based composites filled with flake and whisker type hexagonal boron nitride materials

2020 ◽  
pp. 095400832095941
Author(s):  
Rongkun Yang ◽  
Mingming Sheng ◽  
Yujun Zhang ◽  
Hongyu Gong ◽  
Xiao Lin ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Properties ◽  
Boron Nitride ◽  
Epoxy Resin ◽  
Heat Dissipation ◽  
Hexagonal Boron Nitride ◽  
Transmission Efficiency ◽  
Pure Epoxy ◽  
The Matrix ◽  
Properties Of Composites

In this work, the epoxy-based composites filled with 3-Aminopropyltriethoxysilane (KH-550) modified binary filler of hexagonal boron nitride (h-BN) flakes and h-BN whiskers were fabricated, and the thermal and dielectric properties of composites were systematically investigated. Adding h-BN whiskers to the filler could effectively form heat conduction paths and improve the phonon transmission efficiency, thereby improving the thermal conductivity of the composites. According to our results, the thermal conductivity of composite with 27 wt% h-BN flakes and 3 wt% h-BN whiskers reached up to 0.819 W·m−1·K−1, which was 3.9 times that of pure epoxy resin. At the same time, the dielectric loss value and dielectric constant of this composite at 1 MHz were 0.02678 and 4.55, respectively, while pure epoxy resin were 0.03602 and 4.33. In addition, introducing h-BN whiskers into the matrix could effectively improve the thermal stability and heat dissipation performance of composites.

scholarly journals Stability of Nonlinear Autonomous Quadratic Discrete Systems in the Critical Case

2010 ◽  
Vol 2010 ◽  
pp. 1-23 ◽  
Author(s):  
Josef Diblík ◽  
Denys Ya. Khusainov ◽  
Irina V. Grytsay ◽  
Zdenĕk Šmarda
Keyword(s):  
Lyapunov Functions ◽  
Critical Case ◽  
Autonomous Systems ◽  
Discrete Systems ◽  
Simple Eigenvalue ◽  
Discrete Equations ◽  
The Matrix ◽  
The Stability ◽  
Important Characterization

Many processes are mathematically simulated by systems of discrete equations with quadratic right-hand sides. Their stability is thought of as a very important characterization of the process. In this paper, the method of Lyapunov functions is used to derive classes of stable quadratic discrete autonomous systems in a critical case in the presence of a simple eigenvalueλ=1of the matrix of linear terms. In addition to the stability investigation, we also estimate stability domains.

scholarly journals Solvent-assisted encapsulation of boron nitride in polystyrene for high-efficient heat dissipation

2021 ◽  
pp. 107325
Author(s):  
Weifang Han ◽  
Mengyuan Chen ◽  
Wei Li ◽  
Yuchao Li ◽  
Chunhua Ge ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Heat Dissipation ◽  
High Efficient

scholarly journals Coupled THM and Matrix Stability Modeling of Hydroshearing Stimulation in a Coupled Fracture-Matrix Hot Volcanic System

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Yong Xiao ◽  
Jianchun Guo ◽  
Hehua Wang ◽  
Lize Lu ◽  
John McLennan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conduction ◽  
Dominant Role ◽  
Injection Well ◽  
Time Step ◽  
Volcanic System ◽  
Induced Stress ◽  
The Matrix ◽  
Matrix Stability ◽  
The Stability

A coupled thermal-hydraulic-mechanical (THM) model is developed to simulate the combined effect of fracture fluid flow, heat transfer from the matrix to injected fluid, and shearing dilation behaviors in a coupled fracture-matrix hot volcanic reservoir system. Fluid flows in the fracture are calculated based on the cubic law. Heat transfer within the fracture involved is thermal conduction, thermal advection, and thermal dispersion; within the reservoir matrix, thermal conduction is the only mode of heat transfer. In view of the expansion of the fracture network, deformation and thermal-induced stress model are added to the matrix node’s in situ stress environment in each time step to analyze the stability of the matrix. A series of results from the coupled THM model, induced stress, and matrix stability indicate that thermal-induced aperture plays a dominant role near the injection well to enhance the conductivity of the fracture. Away from the injection well, the conductivity of the fracture is contributed by shear dilation. The induced stress has the maximum value at the injection point; the deformation-induced stress has large value with smaller affected range; on the contrary, thermal-induced stress has small value with larger affected range. Matrix stability simulation results indicate that the stability of the matrix nodes may be destroyed; this mechanism is helpful to create complex fracture networks.

scholarly journals Thermal Stability of Residual Stresses in Differently Deep Rolled Surface Layers of Steel SAE 1045

2021 ◽  
Author(s):  
Stephanie Saalfeld ◽  
Thomas Wegener ◽  
Berthold Scholtes ◽  
Thomas Niendorf
Keyword(s):  
Thermal Stability ◽  
Elevated Temperature ◽  
Residual Stresses ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Decisive Role ◽  
Deep Rolling ◽  
Material Conditions ◽  
The Stability ◽  
Thermal Stability Of

AbstractThe stability of compressive residual stresses generated by deep rolling plays a decisive role on the fatigue behavior of specimens and components, respectively. In this regard, deep rolling at elevated temperature has proven to be very effective in stabilizing residual stresses when fatigue analysis is conducted at ambient temperature. However, since residual stresses can be affected not only by plastic deformation but also when thermal energy is provided, it is necessary to analyze the influence of temperature and time on the relaxation behavior of residual stresses at elevated temperature. To evaluate the effect of deep rolling at elevated temperatures on stability limits under thermal as well as combined thermo-mechanical loads, the present work introduces and discusses the results of investigations on the thermal stability of residual stresses in differently deep rolled material conditions of the steel SAE 1045.

Investigation of Thermochemical Hydrogen Production via the Novel Thermo-Mechanical Stabilized Iron Oxide-Zirconia Porous Structure

2013 ◽  
Author(s):  
Ayyoub M. Mehdizadeh ◽  
Kelvin Randhir ◽  
James F. Klausner ◽  
Nicholas AuYeung ◽  
Fotouh Al-Raqom ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Porous Structure ◽  
Chemical Reactivity ◽  
Thermal Reduction ◽  
The Novel ◽  
Concentrated Solar Energy ◽  
The Matrix ◽  
Unique Method ◽  
Laboratory Scale Reactor ◽  
The Stability

In this study we have developed a unique method for synthesizing very reactive water splitting materials that will remain stable at temperatures as high as 1450 °C to efficiently produce clean hydrogen from concentrated solar energy. The hydrogen production for a laboratory scale reactor using a “Thermo-mechanical Stabilized Porous Structure” (TSPS) is experimentally investigated for oxidation and thermal reduction temperatures of 1200 and 1450 °C, respectively. The stability and reactivity of a 10 g TSPS over many consecutive oxidation and thermal reduction cycles for different particle size ranges has been investigated. The novel thermo-mechanical stabilization exploits sintering and controls the geometry of the matrix of particles inside the structure in a favorable manner so that the chemical reactivity of the structure remains intact. The experimental results demonstrate that this structure yields peak hydrogen production rates of 1–2 cm3/(min.gFe3O4) during the oxidation step at 1200 °C and the 30 minute thermal reduction step at 1450 ° C without noticeable degradation over many consecutive cycles. The hydrogen production rate is one of the highest yet reported in the open literature for thermochemical looping processes using thermal reduction. This novel process has strong potential for developing an enabling technology for efficient and commercially viable solar fuel production.

Cutting tool wear in the machining of hardened steels

Wear ◽  
2001 ◽  
Vol 247 (2) ◽  
pp. 152-160 ◽  
Author(s):  
J Barry ◽  
G Byrne
Keyword(s):  
Tool Wear ◽  
Cutting Tool ◽  
Hardened Steels ◽  
Cutting Tool Wear
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