Sintering of Fine Grained Polycrystalline Cubic Boron Nitride Compacts without Binder

2014 ◽  
Vol 665 ◽  
pp. 79-84
Author(s):  
Guo Duan Liu ◽  
Zi Li Kou ◽  
Xiao Zhi Yan ◽  
Li Lei ◽  
Duan Wei He
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Cubic Boron Nitride ◽  
High Hardness ◽  
Industrial Applications ◽  
X Ray Diffraction ◽  
Fine Grained ◽  
Hard Materials ◽  
Different Temperatures ◽  
Superior Mechanical Properties

Cubic boron nitride (cBN) is a excellent super hard materials with superior mechanical properties that has been widely used in different industrial applications. Conventional cBN was sintered with binder in the cBN powder, and the binder affect the mechanical properties of cBN. Here we report that we sinter the polycrystalline cBN on WC-16wt%Co substrates without any sintering agent at the pressure 5.5 GPa and temperatures of 1300-1600°C for 10 min. In the sintering, we used 1-2μm fine grained cBN powder as the starting materials, also, liquid substance infiltrated from the substrates and occurred chemical reactions with cBN powder. Reaction contents were investigated at different temperatures according to X-ray diffraction (XRD). Plenty of direct BN-BN bonding was formed in the scanning electron microscopy ( SEM) observation.The hardness of best samples reach 38.5 GPa under the loading force of 5 kg, which have high hardness for the formation of direct BN-BN fine grains in the sample. .

scholarly journals Influence of binder systems on sintering characteristics, microstructures, and mechanical properties of PcBN composites fabricated by SPS

2022 ◽  
Vol 11 (2) ◽  
pp. 321-330
Author(s):  
Shuna Chen ◽  
Hengzhong Fan ◽  
Yunfeng Su ◽  
Wensheng Li ◽  
Jicheng Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Bonding Strength ◽  
Cubic Boron Nitride ◽  
Critical Factor ◽  
High Hardness ◽  
High Porosity ◽  
Plasma Sintering ◽  
Mechanical Performances ◽  
Sintering Characteristics

AbstractCubic boron nitride (cBN) with high hardness, thermal conductivity, wear resistance, and chemical inertness has become the most promising abrasive and machining material. Due to the difficulty of fabricating pure cBN body, generally, some binders are incorporated among cBN particles to prepare polycrystalline cubic boron nitride (PcBN). Hence, the binders play a critical factor to the performances of PcBN composites. In this study, the PcBN composites with three binder systems containing ceramic and metal phases were fabricated by spark plasma sintering (SPS) from 1400 to 1700 °C. The sintering behaviors and mechanical properties of the composites were investigated. Results show that the effect of binder formulas on mechanical properties mainly related to the compactness, mechanical performances, and thermal expansion coefficient of binder phases, which affect the carrying capacity of the composites and the bonding strength between binder phases and cBN particles. The PcBN composite with SiAlON phase as binder presented optimal flexural strength (465±29 MPa) and fracture toughness (5.62±0.37 MPa·m1/2), attributing to the synergistic effect similar to transgranular and intergranular fractures. Meanwhile, the excellent mechanical properties can be maintained a comparable level when the temperature even rises to 800 °C. Due to the weak bonding strength and high porosity, the PcBN composites with Al2O3-ZrO2(3Y) and Al-Ti binder systems exhibited inferior mechanical properties. The possible mechanisms to explain these results were also analyzed.

Microstructural studies of boron nitride films deposited by microwave plasma-assisted chemical vapor deposition by using trimethyl borazine precursor

1999 ◽  
Vol 14 (3) ◽  
pp. 829-833 ◽  
Author(s):  
A. Ratna Phani
Keyword(s):  
Boron Nitride ◽  
Microwave Plasma ◽  
Cubic Boron Nitride ◽  
Chemical Vapor ◽  
Interplanar Distance ◽  
Stoichiometric Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Deposited Films

Thin films of cubic boron nitride (c-BN) were synthesized using an organometallic precursor trimethylborazine (TMB) which contains both boron and nitrogen in 1 : 1 stoichiometric ratio. The films were deposited at different temperatures ranging from 300 to 500 °C at a pressure of 2 Torr and at 360 W microwave power, using N2 as carrier gas. The deposited films were characterized by Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), and scanning electron microscopy (SEM), which reveal the presence of amorphous BN and crystalline c-BN in varying proportions. The x-ray diffraction pattern of the deposited films showed a strongest peak at 2θ = 57.1° where the interplanar distance value, d = 2.06 Å, agreed well with the (111) crystallographic orientation of c-BN phase.

CHARACTERIZATION OF HYDROXYAPATITE/TI6AL4V COMPOSITE POWDER UNDER VARIOUS SINTERING TEMPERATURE

2015 ◽  
Vol 75 (7) ◽  
Author(s):  
Amir Arifin ◽  
Abu Bakar Sulong ◽  
Norhamidi Muhamad ◽  
Junaidi Syarif
Keyword(s):  
Mechanical Properties ◽  
Composite Powder ◽  
Sintering Temperature ◽  
Physical And Mechanical Properties ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Different Temperatures ◽  
Two Phases ◽  
Work Interaction

Hydroxyapatite (HA) has been widely used in biomedical applications due to its excellent biocompatibility. However, Hydroxyapatite possesses poor mechanical properties and only tolerate limited loads for implants. Titanium is well-known materials applied in implant that has advantage in mechanical properties but poor in biocompatibility. The combination of the Titanium alloy and HA is expected to produce bio-implants with good in term of mechanical properties and biocompatabilty. In this work, interaction and mechanical properties of HA/Ti6Al4V was analyzed. The physical and mechanical properties of HA/Ti6Al4V composite powder obtained from compaction (powder metallurgy) of 60 wt.% Ti6Al4V and 40 wt.% HA and sintering at different temperatures in air were investigated in this study. Interactions of the mixed powders were investigated using X-ray diffraction. The hardness and density of the HA/Ti6Al4V composites were also measured. Based on the results of XRD analysis, the oxidation of Ti began at 700 °C. At 1000 °C, two phases were formed (i.e., TiO2 and CaTiO3). The results showed that the hardness HA/Ti6Al4V composites increased by 221.6% with increasing sintering temperature from 700oC to 1000oC. In contrast, the density of the composites decreased by 1.9% with increasing sintering temperature. 

Microstructure and Mechanical Properties Resulting from Conventional Cold Extrusion of Equal Channel Angular Extruded Aluminium Alloy AA6101

2006 ◽  
Vol 503-504 ◽  
pp. 287-292 ◽  
Author(s):  
D. Nagarajan ◽  
Chakkingal Uday ◽  
P. Venugopal
Keyword(s):  
Mechanical Properties ◽  
Equal Channel Angular Extrusion ◽  
Industrial Applications ◽  
Cold Extrusion ◽  
Fine Grained ◽  
Microstructure Evaluation ◽  
Microstructure And Mechanical Properties ◽  
Processing Step ◽  
Deformation Processes ◽  
Extruded Aluminium Alloy

Severe plastic deformation processes like equal channel angular extrusion (ECAE) have been widely investigated for their ability to produce nano/ ultra fine-grained microstructures. It is well known that submicron sized grains/ sub grains can be produced in most Al alloys using this technique. However, industrial applications of ECAE will depend heavily on the advantages conferred by this process when it is used as an intermediate processing step prior to conventional forming. In the current investigation, the influence of pre processing by ECAE on subsequent post processing by conventional cold extrusion has been investigated. ECAE extrusion was carried out on cylindrical specimens of AA 6101 using an ECAE die with a die angle of 120 degrees. Extrusion was carried out for three passes using two different processing routes. The ECA extruded specimens were subsequently subjected to conventional cold extrusion. The differences in extrusion pressures, which have a strong influence on industrial applications, were noted. Changes in microstructure and mechanical properties were also determined. The obtained results of mechanical properties and microstructure evaluation show that for high strains (strain ε ≈ 2.01), ECAE through some processing routes can be effectively used as an intermediate processing step prior to conventional cold extrusion to obtain a product with enhanced mechanical properties.

Microstructure and Mechanical Properties of Fe-Cu-Ni Sinters Prepared by Ball Milling and Hot Pressing

2020 ◽  
Vol 405 ◽  
pp. 379-384
Author(s):  
Joanna Borowiecka-Jamrozek ◽  
Jan Lachowski
Keyword(s):  
Mechanical Properties ◽  
Hot Pressing ◽  
High Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Composition ◽  
Microstructure And Mechanical Properties ◽  
Static Tensile ◽  
Iron Based ◽  
Surface Observations

The main purpose of this work was to determine the effect of the powder composition on the microstructure and properties of iron-based sinters used as a matrix in diamond tools. The Fe-Cu-Ni sinters obtained from a mixture of ground powders were used for experiments. The influence of manufacturing process parameters on the microstructure and mechanical properties of sinters was investigated. Sintering was performed using hot-pressing technique in a graphite mould. The investigations of obtained sinters included: density, hardness, static tensile test, X-ray diffraction analysis, microstructure and fracture surface observations. The obtained results indicate that the produced sinters have good plasticity and relatively high hardness.

scholarly journals Influence of Temperature on Mechanical Properties of P(BAMO-r-THF) Elastomer

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2507
Author(s):  
Jinxian Zhai ◽  
Hanpeng Zhao ◽  
Xiaoyan Guo ◽  
Xiaodong Li ◽  
Tinglu Song
Keyword(s):  
Mechanical Properties ◽  
X Ray Diffraction ◽  
Polymeric Chains ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Strain Induced Crystallization ◽  
Thermal Histories ◽  
Static Conditions ◽  
The Relationship ◽  
Induced Crystallization

The relationship between temperature and the mechanical properties of an end cross-linked equal molar random copolyether elastomer of 3,3-bis(azidomethyl)oxetane and tetrahydrofuran (P(BAMO-r-THF)) was investigated. During this investigation, the performances of two P(BAMO-r-THF) elastomers with different thermal histories were compared at different temperatures. The elastomer as prepared at 20 °C (denoted as S0) exhibited semi-crystallization morphology. Wide angle X-ray diffraction analysis indicated that the crystal grains within elastomer S0 result from the crystallization of BAMO micro-blocks embedded in P(BAMO-r-THF) polymeric chains, and the crystallinity is temperature irreversible under static conditions. After undergoing a heating-cooling cycle, this elastomer became an amorphous elastomer (denoted as S1). Regarding mechanical properties, at 20 °C, break strains and stresses of 315 ± 22% and 0.46 ± 0.01 MPa were obtained for elastomer S0; corresponding values of 294 ± 6% and 0.32 ± 0.02 MPa were obtained for elastomer S1. At −40 °C, these strains and stresses simultaneously increased to 1085 ± 21% and 8.90 ± 0.72 MPa (S0) and 1181 ± 25% and 10.23 ± 0.44 MPa (S1), respectively, owing to the strain-induced crystallization of BAMO micro-blocks within the P(BAMO-r-THF) polymeric chains.

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HYPEREUTECTIC Al-Si/AlNp COMPOSITE

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1377-1382 ◽  
Author(s):  
SEULKI PARK ◽  
JINMYUNG CHOI ◽  
BONGGYU PARK ◽  
IKMIN PARK ◽  
YONGHO PARK ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Dispersive Spectrometer ◽  
Microstructural Characterization ◽  
Weight Fraction ◽  
Reinforcement Particle ◽  
Hot Press ◽  
X Ray Diffraction ◽  
X Ray ◽  
Superior Mechanical Properties ◽  
Phase Evaluation

Hypereutectic Al - Si alloys with fine and evenly distributed Si precipitates have superior mechanical properties In this study, hypereutectic Al - Si alloy powders which contained 15 and 20wt% Si were prepared by a gas atomization process. 1, 3 and 5wt% AlN particles were blended with the Al - Si alloy powders using turbular mixer. The mixture was consolidated by Hot Press at 550°C for 1h under 60MPa. Relative density of the sintered samples was about 98% of theoretical density. This study was investigated by two ways. One is the effect of reinforcement weight fraction and the other is the effect of Silicon contents on the mechanical properties of the composite. Microstructural characterization and phase evaluation were carried out using X-ray Diffraction, Scanning Electron Microscopy equipped with Energy Dispersive Spectrometer. The results showed that the smaller the reinforcement particle size was and the better its distribution was, the higher ultimate tensile strength and hardness were.

Manufacturing and Properties of Tungsten Carbide-Oxide Composites

2017 ◽  
Vol 742 ◽  
pp. 223-230 ◽  
Author(s):  
Anne Vornberger ◽  
Johannes Pötschke ◽  
Christian Berger
Keyword(s):  
Mechanical Properties ◽  
Tungsten Carbide ◽  
Metal Content ◽  
High Hardness ◽  
Metal Carbide ◽  
Hard Materials ◽  
Binder Free ◽  
Oxide Composites ◽  
Hardness Values ◽  
Binder Metal

Conventional WC-Co hardmetals are widely used in various applications due to their excellent properties. High hardness can be achieved using compositions with little to no content of cobalt or nickel. These binder metals are hazardous to health, making a substitution not only desirable because of availability and cost reasons. A new possibility to manufacture such hard materials is the combination of tungsten carbide with oxides such as Al2O3 and ZrO2. In this way the binder metal content can be replaced. Furthermore the content of the also expensive WC can be reduced. Such metal carbide – oxide composites with oxide contents between 16 vol% and 40 vol% were manufactured. The completely dense composites feature high hardness values of 2000 HV10 to 2400 HV10 while also having an acceptable fracture toughness of up to 7 MPa⋅m1/2. The improved mechanical properties make the replacement of WC-Co hardmetals and binder free WC ceramics in special areas possible.

scholarly journals Mechanical properties of ultra-hard nanocrystalline cubic boron nitride

2019 ◽  
Vol 126 (7) ◽  
pp. 075107 ◽  
Author(s):  
Vladimir L. Solozhenko ◽  
Volodymyr Bushlya ◽  
Jinming Zhou
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Cubic Boron Nitride

Microstructure and Properties of Hot-Pressing Sintered Tungsten Carbide Composites by Adding Cubic Boron Nitride

2015 ◽  
Vol 655 ◽  
pp. 45-48
Author(s):  
Kun Li ◽  
Hai Yan Chen ◽  
Qiu Shuang He ◽  
Li Hua Dong
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Flexural Strength ◽  
Tungsten Carbide ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Cubic Boron Nitride ◽  
Microstructure And Mechanical Properties ◽  
Hot Pressing Sintering ◽  
Sintering Method

(0, 5, 10, 15, 20) vol% CBN-WC/Co composites were consolidated by ball milling and the following hot-pressing sintering method. WC, Co and CBN powders were used as the starting materials. The effects of the CBN content on the density, microstructure and mechanical properties of CBN-WC/Co composites were investigated. The results showed that the CBN content had remarkable influence on the microstructure and mechanical properties of CBN-WC/Co Composites. With the increasing content of CBN, the density decrease, while Vickers hardness and flexural strength increased initially to the maximum values and then decreased at CBN 10 vol%. When 10 vol% CBN-WC/Co powders were hot-pressing sintered at 1350°C and 20MPa for 90 min, an excellent Vickers hardness of 19.8GPa was achieved, combining a flexural strength of 682MPa.

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