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2023 Vol. 28, No. 2
Published: 2023-04-15
Engineering and Technology
Theoretical Research
Theoretical Research
93
Simulation of crack propagation and mechanical properties prediction of graphene-carbon nanotubes/WC ceramic tool materials
ZHAO Wenlong, SUN Jialin, HUANG Zhifu, ZHAO Le, LI Xiao
DOI: 10.19976/j.cnki.43-1448/TF.2022069
The rapid development of computer simulation technology provides theoretical and technical support for the performance prediction and high-throughput preparation of ceramic tool materials. In this paper, a parametric model and mechanical property prediction model of WC ceramic tool materials containing graphene (G) and carbon nanotube (CNT) were constructed based on Python software. The influence of G-CNT on the microstructure and crack propagation behavior of tool materials was mainly studied. The results show that the three-dimensional G-CNT spatial structure can further improve the properties of WC ceramics compared with single G. When the mass fraction of G-CNT is 0.4%, the tool material has the best comprehensive mechanical properties. The strengthening and toughening mechanism mainly include the super-mixed distribution of G-CNT strong and weak interfaces, material fracture mode transformation, crack deflection, etc.
2023 Vol. 28 (2): 93-112 [
Abstract
] (
1200
)
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1424
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Engineering and Technology
113
Fabrication of cylindrical Si
3
N
4
ceramics by spark plasma sintering based on the powder bed technology
CAI Peibin, GU Qiankun, GUO Weiming, LUO Sichun, LIN Huatai
DOI: 10.19976/j.cnki.43-1448/TF.2022083
SiC powders with average particle sizes of 150 μm and 50 μm were mixed with graphite powders with average particle sizes of 150 μm and 50 μm respectively to obtain coarse particle size powder bed (150 μm SiC+150 μm graphite) and fine particle size (50 μm SiC+50 μm graphite); the volume fractions of SiC and graphite in the powder bed were both 50%. Pre-sintered cylindrical Si
3
N
4
green body was sintered by spark plasma sintering (SPS) based on powder bed technology. The effects of two different particle size bed powders, pre-sintering temperature (1 400 ℃and 1 500 ℃) and powder bed recovery on the deformation degree, density, phase composition and microstructure of cylindrical Si
3
N
4
ceramics were investigated. The research results show that the circular section retention of cylindrical Si
3
N
4
ceramic prepared by combining the coarse particle size powder bed, a pre-sintering temperature of 1 500 ℃ and a recycled once powder bed is the best, reaching 93%; the Vickers hardness and fracture toughness are (18.73±0.24) GPa and (3.64±0.23) MPa·m
1/2
, respectively. Due to the low sintering temperature (1 500 ℃), the main phase of the as-sintered ceramics is α-Si
3
N
4
; the grain morphology is equiaxed. This study shows that the shape limitation of the Si
3
N
4
ceramics prepared by SPS can be overcame by introducing the powder bed. This technology is expected to realize the preparation of high-performance Si
3
N
4
ceramics with complex shapes.
2023 Vol. 28 (2): 113-119 [
Abstract
] (
480
)
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(577 KB) (
645
)
120
Effect of TaC on high temperature ablative resistance of SiC coatings
LUO Xiao, CHEN Yesong, KANG Pan, FANG Jia, YANG Xin, HUANG Qizhong
DOI: 10.19976/j.cnki.43-1448/TF.2022090
SiC coating and SiC-TaC composite coating were prepared on the surface of C/C composites by embedding reaction process using Si and Ta
2
O
5
powders as raw materials. The effects of TaC on the microstructure and high temperature ablation resistance of SiC coating were studied by X-ray diffraction, scanning electron microscopy and high temperature plasma flame (about 2 300 ℃) ablation experiments. The results show that addition of TaC can effectively improve the ablation resistance of SiC coating. After ablation under plasma flame for 30 s, the mass and linear ablation rates of SiC coating are (0.189 2±0.080 0) mg/s and (1.386 7±0.120 0) μm/s, respectively. With addition of TaC phase, the mass and linear ablation rates of SiC-TaC coating are (0.062 7± 0.050 0) mg/s and (0.893 9±0.070 0) μm/s, respectively, the mass and linear ablation rates of SiC-TaC coating are decreased by 66.86% and 35.54%, respectively. The improvement of high-temperature ablation resistance of SiC-TaC composite coating is mainly related to the enhancement of high-temperature stability of the coating and the self-healing cooperation of molten Ta
2
O
5
phase during ablation.
2023 Vol. 28 (2): 120-128 [
Abstract
] (
611
)
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1275
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129
Preparation and magnetochromic discoloration of ferroferric oxide magnetically responsive photonic crystals
TIAN Zhaoxia, WU Zhisheng, XIAO Wei, XU Gaojie, LIU Fenghua
DOI: 10.19976/j.cnki.43-1448/TF.2023001
Magnetically responsive ferroferric oxide (Fe
3
O
4
) nanoparticles were prepared by solvothermal method using ferric trichoride (FeCl
3
) as the iron source and poly (styrene sulfonic acid-co-maleic acid) (PSSMA) sodium salt with two different chemical structures as surfactants. The effects of PSSMA surfactants with different structures and reaction conditions on the morphology, particle size, and photonic properties of Fe
3
O
4
nanoparticles were investigated. The results show that the Fe
3
O
4
particles are nearly spherical and surface is rough when using PSSMA with
n
(SS)∶
n
(MA)=1∶1 as surfactant in strong alkali environment, and particle size increases with increasing water content. Using PSSMA with
n
(SS)∶
n
(MA)=3∶1 as surfactant in weak alkali environment, the particles are regular spherical and surface is smooth, and the size increases with increasing Fe
3+
content. It is more suitable for the generation of superparamagnetic Fe
3
O
4
nanoparticles with uniform particle size and good monodispersity in weak alkaline environment due to the more abundant sulfonic acid group on the surface. This Fe
3
O
4
nanoparticle dispersion system can rapidly form ordered photonic crystal nanoparticles under the action of external magnetic field, and obtain excellent tunable structure color.
2023 Vol. 28 (2): 129-140 [
Abstract
] (
752
)
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2600
)
141
Microstructure and mechanical properties of WC-10Co cemented carbide prepared by extrusion 3D printing
ZHU Xianzhi, CHENG Huichao, ZHOU Chengshang, LIU Yong
DOI: 10.19976/j.cnki.43-1448/TF.2023009
The traditional method of preparing cemented carbide products with complex components is difficult and costly, which affects the sustainable development of cemented carbide. The cemented carbide samples were formed by extrusion 3D printing. The sintered cemented carbide samples of WC-10Co were prepared by solvent degreasing, hot degreasing and air pressure sintering. The effects of printing parameters, degreasing process and sintering temperature on the microstructure and mechanical properties of the samples were studied. The results show that the surface roughness and dimensional accuracy of the printed samples can be adjusted by using different nozzle sizes. The shape and size of the blank are stable after degreasing by solvent-thermal two-step degreasing method. The microstructure of the alloy is uniformly distributed after sintering. After sintering at 1 450 ℃, the hardness of the alloy is 87.3 HRA, the bending strength is more than 3 500 MPa, and the performance is comparable to that prepared by conventional powder metallurgy method.
2023 Vol. 28 (2): 141-150 [
Abstract
] (
590
)
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(1649 KB) (
823
)
151
Structure and laser absorption property of Sm
3+
/Ce
3+
co-doped B
2
O
3
-Al
2
O
3
-SiO
2
glasses
LÜ Xuejuan, SU Yuchang, WANG Lirong, LU Qingye
DOI: 10.19976/j.cnki.43-1448/TF.2023012
B
2
O
3
-Al
2
O
3
-SiO
2
-Sm
2
O
3
-
x
CeO
2
(
x
is 0-6%, molar fraction) glasses were prepared by solid-phase melting method with Sm
3+
/Ce
3+
co-doping in boron-aluminosilicate glasses (composition 43B
2
O
3
-25Al
2
O
3
-32SiO
2
) with the help of X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV-Vis-NIR spectrophotometer (UV-VIS-NIR) and other characterization methods to study the structure and laser absorption properties of the glasses. The results show that all samples are glassy with uniform distribution of Sm
3+
and Ce
3+
. The percentage of bridging oxygen in the glasses increases from 60.12% to 63.82% with the CeO
2
molar fraction increasing from 0 to 2%, and decreases to 59.41% when the CeO
2
molar fraction increases to 6%. The laser absorption performance of the glasses is best at 2%CeO
2
molar fraction, with the diffuse absorption peak at 1 076 nm and the diffuse reflectance of 48.10%. The Sm
3+
/Ce
3+
co-doped boron-aluminosilicate glass is a promising material for laser absorption at 1.06 μm wavelength.
2023 Vol. 28 (2): 151-159 [
Abstract
] (
375
)
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(609 KB) (
824
)
160
Viscosity control of silicon carbide/carbon black suspension for gel casting
GUO Jinyu, NI Zhentao, LIU Peng, YANG Xiaole, LI Yuanbing, YANG Xianfeng
DOI: 10.19976/j.cnki.43-1448/TF.2022093
SiC/carbon black paste for gel casting was prepared, the viscosity and stability of the paste were measured by rotary viscometer and Zeta potential measuring instrument. The effects of polyvinylpyrrolidone (PVP) and processing parameters on the dispersion of carbon black were studied, and the main factors affecting the viscosity of SiC/carbon black suspension for gel casting were analyzed. The results show that the adsorption of PVP on the surface of carbon black particles can increase the absolute value of the Zeta potential of carbon black in water, and also can increase the steric repulsion between carbon black particles, thus the dispersion of carbon black particles in water is improved. The optimal amount of PVP addition to the carbon black slurry is 2.25 mg/m
2
, and the proposed ball milling time of the slurry is 9 h. Under the optimized process conditions that the grading of coarse and fine silicon carbide particles is 2∶1, the mass fraction of carbon black is 6%, and the mass fraction of monomer is 15%, the viscosity of the slurry is moderate, and it is suitable for gel casting of slurry with high solid content.
2023 Vol. 28 (2): 160-169 [
Abstract
] (
407
)
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(731 KB) (
745
)
170
Process optimization, microstructure and mechanical properties of Al-Ce-Sc-Zr alloy by selective laser melting
YANG Ziwei, CHEN Chao, WU Yiyou, ZHOU Kechao
DOI: 10.19976/j.cnki.43-1448/TF.2023004
Al-Ce-Sc-Zr alloy was performed by selective laser melting (SLM) using gas atomization Al-10Ce-0.4Sc-0.2Zr (mass fraction) pre-alloyed powders as raw materials. The effects of laser power and scanning speed on the relative density and mechanical properties of the alloy were studied by optical microscopy and room temperature tensile test to optimize the process parameters. X-ray diffractometer, scanning electron microscope and transmission electron microscope were also used to study the eutectic microstructure morphology, phase composition and grain size of the alloy prepared by SLM under the optimal process parameters. The results show that the relationship between laser power, scanning speed and the relative density, mechanical properties of the alloy are non-linear, with the increase of laser energy density, the relative density and mechanical properties of the alloy show a trend of increasing and then decreasing. The optimum parameters are laser power of 350 W and scanning speed of 2 000 mm/s. The relative density of Al-Ce-Sc-Zr alloy after process optimization can reach 99.92% with tensile strength of (441±3) MPa, yield strength of (370±18) MPa and elongation of (9.4±0.9)%. The as-built Al-Ce-Sc-Zr alloy presents a columnar-equiaxed bimodal grain structure. The grain orientation is relatively random, indicating that no strong texture is formed. The alloy consists of α-Al and Al
11
Ce
3
phases. Sc and Zr atoms are mainly presented as the form of solid solution in α-Al matrix. The eutectic Al
11
Ce
3
phase has an irregular ribbonlike morphology with an average width of 35 nm and is arranged in a complex discontinuous network. The eutectic microstructure is very fine and uniformly distributed.
2023 Vol. 28 (2): 170-179 [
Abstract
] (
742
)
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1023
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180
Effect of cemented carbide grain size on diamond coating
HUA Tengyu, XIA Xin, MA Li, WEI Qiuping, SHI Pengcheng
DOI: 10.19976/j.cnki.43-1448/TF.2023013
Boron-doped diamond coatings were deposited on YG6 cemented carbide substrates with different grain sizes (0.4, 0.6, 1.0 and 2.0 μm) by hot wire chemical vapor deposition. The morphology and composition of the cemented carbide substrates were characterized, and the morphology, structure, composition and adhesion of the diamond coating were also analyzed by scanning electron microscope, X-ray diffraction, Raman spectroscopy and Rockwell hardness tester. The effects of grain size of cemented carbide substrates on the growth and adhesion properties of diamond coatings were studied and compared. The results show that with the grain size of cemented carbide increasing from 0.4 μm to 2.0 μm, the grain size of diamond gradually increases and its uniformity is better. The peak intensity ratio (
I
D
/
I
G
) of diamond and graphite Raman peaks increases from 4.74 to 6.53. There is a good correlation between the film substrate bonding performance and the internal stress of the coating, as well as the half peak width of diamond, which are affected by the grain mismatch of the matrix alloy, while the internal stress of the coating is also affected by boron doping. When the cemented carbide grain size is 2.0 μm, the diamond coating has the maximum
I
D
/
I
G
ratio of 6.53. The internal stress of diamond coating is also the lowest, which is only 1.588 GPa. And the film-substrates adhesion is optimal that can reach the HF1 level under the pressure of 600 N.
2023 Vol. 28 (2): 180-191 [
Abstract
] (
420
)
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1055
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192
Microstructure and properties of Sc, Y microalloyed René104 nickel-based superalloy powders prepared by argon atomization
CAO Bin, LIU Zuming, WANG Jianchuan, WEI Bing, ZHOU Huan, ZHANG Yazhou
DOI: 10.19976/j.cnki.43-1448/TF.2022054
Sc, Y microalloyed René104 nickel-based superalloy powders were prepared by argon atomization. The particle size distribution, morphology, microstructure and properties of the powders were analyzed. The results show that the argon atomized powders have high sphericity with less satellite powders and irregular powders, and the yield (mass fraction) of the powders with particle size less than 53 μm is as high as 52.52%. The interior microstructure of the powder is dense, showing both equiaxial grain and dendrite morphology. Ti, Nb, Ta and Mo segregate at the grain boundary. By Sc, Y microalloying, the properties of René104 nickel-based superalloy powders have been improved, with good flow ability and high apparent density. Microhardness, nanohardness (HV) and elastic modulus of the powders are 360±6, (6.5±0.4) GPa and (102.1±10.6 ) GPa, respectively.
2023 Vol. 28 (2): 192-202 [
Abstract
] (
371
)
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