The enhancement of the microstructure and mechanical performances of ultrafine WC-Co cemented carbides by optimizing Cr2(C,N) addition and WC particle sizes

2021 ◽  
Vol 97 ◽  
pp. 105518
Author(s):  
Ding Li ◽  
Ying Liu ◽  
Jinwen Ye ◽  
Xianfu Chen ◽  
Lu Wang
Keyword(s):  
Cemented Carbides ◽  
Particle Sizes ◽  
N Addition ◽  
Mechanical Performances

scholarly journals Effect of particle size and amount of nonmetallic PCB materials on the mechanical properties of rHDPE/PCB composites

2019 ◽  
Vol 15 (2) ◽  
pp. 260-267
Author(s):  
Johan Sohaili ◽  
Shantha Kumari Muniyandi ◽  
Siti Suhaila Mohamad ◽  
Azreen Ariffin
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Printed Circuit Board ◽  
Glass Fibers ◽  
Circuit Board ◽  
Chemical Compositions ◽  
Particle Sizes ◽  
Melt Compounding ◽  
Mechanical Performances ◽  
Fiber Materials

Composites based on recycled high density polyethylene (rHDPE) and nonmetallic printed circuit board (PCB)  waste were made through melt compounding and compression molding. In this study, the chemical compositions of the nonmetallic PCB material were determined via XRF and it was confirmed that it contains predominantly  72.7% of glass fiber materials which improve the mechanical performances of the rHDPE matrix. The main aim of this study is to determine the effect of different particle sizes and loadings of nonmetallic PCB on mechanical properties of rHDPE/PCB composite. The results indicated that mechanical properties of composites were excellent when nonmetallic materials with particle size from 0.09 to 0.15 mm and adding amount was 30 wt%. Microscopic images revealed that nonmetallic particles with the size of 0.07-0.09 mm and 0.09 -0.15 mm contained majority of single glass fibers whereas, bigger particle sizes of 0.15-0.3 mm and 0.3-0.5 mm, contained glass fibers in the form of bundles and large resin sheet.

scholarly journals Mechanical Performances of Typical Robot Feet Intruding into Sands

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1867
Author(s):  
Dianlei Han ◽  
Rui Zhang ◽  
Hua Zhang ◽  
Zhenyu Hu ◽  
Jianqiao Li
Keyword(s):  
Quartz Sand ◽  
The Other ◽  
Legged Robots ◽  
Spherical Particles ◽  
Particle Sizes ◽  
Resistive Force ◽  
The Media ◽  
Resistive Forces ◽  
Mechanical Performances ◽  
Particle Shapes

Four kinds of feet with typical structures, referred to as the hemispherical foot, the semicylindrical foot, the rectangular foot and the circular foot, respectively, were designed and manufactured to study the foot–terrain interaction mechanics for legged robots. Three kinds of quartz sand were selected to study how particle size, shape and compactness affected the physical properties of the substrate and the intrusion performance of mechanical feet. The media with smaller particle sizes had higher bulk densities and lower angles of stability, but no obvious rule was found for particle shapes of quartz sand with different sizes. The intrusion resistive forces and pressures of the hemispherical foot on these three kinds of quartz sand were all less compared with the other three mechanical feet. The particle disturbance areas and motion trends were compared under these four kinds of mechanical feet using discrete element method simulations. The intrusion resistive forces of these mechanical feet first increased and then decreased with the increasing particle sizes of the quartz sand. Moreover, the intrusion resistive forces of these mechanical feet on spherical particles were smaller compared with irregular particles. The corresponding resistive forces of the mechanical feet were characterized based on the compactness of the quartz sand. According to the intrusion test data, the classic pressure–sinkage model was modified, and the relationships between intrusion resistive force and mechanical foot depth were obtained.

A Novel Combined Electromagnetic Treatment on Cemented Carbides for Improved Milling and Mechanical Performances

2018 ◽  
Vol 49 (10) ◽  
pp. 4798-4808 ◽  
Author(s):  
Jian Liu ◽  
Can Wei ◽  
Gang Yang ◽  
Libo Wang ◽  
Lin Wang ◽  
...  
Keyword(s):  
Cemented Carbides ◽  
Electromagnetic Treatment ◽  
Mechanical Performances

Characterization of carbides in M50NiL

1991 ◽  
Vol 49 ◽  
pp. 606-607
Author(s):  
L. S. Lin ◽  
K. P. Gumz ◽  
A. V. Karg ◽  
C. C. Law
Keyword(s):  
Temperature Effects ◽  
Base Composition ◽  
Lattice Parameter ◽  
Control Surface ◽  
Carbide Formation ◽  
Particle Sizes ◽  
Low Carbon ◽  
Fee Structure ◽  
Heat Treated

Carbon and temperature effects on carbide formation in the carburized zone of M50NiL are of great importance because they can be used to control surface properties of bearings. A series of homogeneous alloys (with M50NiL as base composition) containing various levels of carbon in the range of 0.15% to 1.5% (in wt.%) and heat treated at temperatures between 650°C to 1100°C were selected for characterizations. Eleven samples were chosen for carbide characterization and chemical analysis and their identifications are listed in Table 1.Five different carbides consisting of M6C, M2C, M7C3 and M23C6 were found in all eleven samples examined as shown in Table 1. M6C carbides (with least carbon) were found to be the major carbide in low carbon alloys (<0.3% C) and their amounts decreased as the carbon content increased. In sample C (0.3% C), most particles (95%) encountered were M6C carbide with a particle sizes range between 0.05 to 0.25 um. The M6C carbide are enriched in both Mo and Fe and have a fee structure with lattice parameter a=1.105 nm (Figure 1).

Microstructure of Electro-Eroded Cemented Carbide Surfaces

1968 ◽  
Vol 26 ◽  
pp. 284-285
Author(s):  
V. N. Filimonenko ◽  
M. H. Richman ◽  
J. Gurland
Keyword(s):  
Surface Layer ◽  
Cobalt Content ◽  
Cemented Carbides ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Metallographic Examination ◽  
Standard Procedures ◽  
Face Centered ◽  
Diamond Paste ◽  
Plastic Carbon

The high temperatures and pressures that are found in a spark gap during electrical discharging lead to a sharp phase transition and structural transformation in the surface layer of cemented carbides containing WC and cobalt. By means of X-ray diffraction both W2C and a high-temperature monocarbide of tungsten (face-centered cubic) were detected after electro-erosion. The W2C forms as a result of the peritectic reaction, WC → W2C+C. The existence and amount of the phases depend on both the energy of the electro-spark discharge and the cobalt content. In the case of a low-energy discharge (i.e. C=0.01μF, V = 300v), WC(f.c.c.) is generally formed in the surface layer. However, at high energies, (e.g. C=30μF, V = 300v), W2C is formed at the surface in preference to the monocarbide. The phase transformations in the surface layer are retarded by the presence of larger percentages of cobalt.Metallographic examination of the electro-eroded surfaces of cemented carbides was carried out on samples with 5-30% cobalt content. The specimens were first metallographically polished using diamond paste and standard procedures and then subjected to various electrical discharges on a Servomet spark machining device. The samples were then repolished and etched in a 3% NH4OH electrolyte at -0.5 amp/cm2. Two stage plastic-carbon replicas were then made and shadowed with chromium at 27°.

TEM study on fine carbide precipitates and dislocation cell structure

1990 ◽  
Vol 48 (4) ◽  
pp. 904-905
Author(s):  
Mengzhe Chen ◽  
Siqin Wang ◽  
Jun Ke
Keyword(s):  
Carbide Particle ◽  
Cell Structure ◽  
Ferrite Matrix ◽  
Dislocation Cell ◽  
Isothermal Treatment ◽  
Particle Sizes ◽  
Dislocation Cell Structure ◽  
Thin Foils ◽  
Hsla Steels ◽  
Fine Carbide

A series of investigations have been conducted into the nature and origin of the dislocation cell structure. R.J.Klassen calculated that the dislocation cell limiting size in pure ferrite matrix is about 0.4 μm. M.N.Bassion estimated the size of dislocation cell in deformed ferrite of HSLA steels to be of the same order.In this paper, TEM observation has been concentrated on the interaction of fine carbide precipitates with dislocation cell structure in deformed Fe-C-V (0.05%C, 0.13% and 0.57%V) and Fe-C-Nb (0.07 %C and 0.04%Nb) alloys and compared with that in Fe-C (0.05%). Specimens were austenitized at 1500 “C/20 min and followed by isothermal treatment at 750 °C and 800 “C for 20, 40 and 120 minutes . The carbide particle sizes in these steels are from 9 to 86nm measured from carbon extraction replicas. Specimens for TEM were cut from differently deformed areas of tensile specimens deformed at room temperture. The thin foils were jet electropolished at -20 C in a solution of 10% perchloric acid and 90% ethanol. The TEM observation was carried out in JEM 100CX , EM420 at 100kv and JEM 2000FX at 200kv.

A High Resolution Study of Alumina Supported Iridium Catalysts

1980 ◽  
Vol 38 ◽  
pp. 202-203
Author(s):  
C. Stoeckert ◽  
B. Etherton ◽  
M. Beer ◽  
J. Gryder
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Metal Particles ◽  
Optical Transfer Function ◽  
Particle Sizes ◽  
Iridium Catalysts ◽  
Transmission Electron ◽  
Optical Transfer ◽  
Conventional Transmission Electron Microscope ◽  
Resolution Study

The interpretation of the activity of catalysts requires information about the sizes of the metal particles, since this has implications for the number of surface atoms available for reaction. To determine the particle dimensions we used a high resolution STEM1. Such an instrument with its simple optical transfer function is far more suitable than a conventional transmission electron microscope for the establishment of particle sizes. We report here our study on the size and number distribution of Ir particles supported on Al2O3 and also examine simple geometric models for the shape of Ir particles.

Sign in / Sign up

Export Citation Format

Share Document