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2024 Vol. 29, No. 4
Published: 2024-08-15
Engineering and Technology
Theoretical Research
Review
Review
255
Research progress on confined ceramic composite armor
ZHANG Maozhe, WANG Zhihui, JI Wei, HOU Shengying, ZHANG Jiaqi, REN Xinming
DOI: 10.19976/j.cnki.43-1448/TF.2024052
Applying certain constraint and pre-stress to the ceramics can change the damage response of the ceramics to the impact and delay the interface defeat, thus improving the penetration resistance of the composite armor. This paper introduced the ballistic mechanism of ceramic composite armor and reviewed the effects of common confined patterns (axial constrained, radial constrained, and three-dimensional constrained) on its ballistic performance, with a view to providing certain reference for the structural design, ballistic mechanism research, and application expansion of ceramic composite armor.
2024 Vol. 29 (4): 255-262 [
Abstract
] (
791
)
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(482 KB) (
342
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Theoretical Research
263
Quality prediction and performance analysis of laser cladding Ni60 alloy coating on 56NiCrMoV7 steel
LIU Lilan, YANG Fan, DOU Weitao, ZHANG Jianguang, HAN Feiyan
DOI: 10.19976/j.cnki.43-1448/TF.2024053
Theoretical and experimental studies on laser cladding of Ni60 alloy powders on 56NiCrMoV7 steel surface were carried out based on response surface method. The laser power, scanning speed, powder feed rate, and overlap rate were taken as the influencing factors, and the multiple regression prediction model was established using the coating surface smoothness, dilution rate, and microhardness as the response targets to optimize the process parameters and predict the coating quality. The results show that the interaction of powder feed rate and scanning speed has the greatest influence on the surface smoothness; the laser power, powder feed rate, and overlap rate have a significant influence on the dilution rate; the powder feed rate has the greatest impact on the microhardness, followed by the laser power. The optimized process parameters are laser power of 1 647 W, powder feed rate of 0.5 rad/min, scanning speed of 5 mm/s, and overlap rate of 0.4, and the predicted values of surface flatness, dilution rate, and microhardness of Ni60 alloy coatings are in good agreement with the experimental values. The metallurgical bonding of Ni60 alloy coating and 56NiCrMoV7 substrate is good, and the hardness and abrasion resistance of the coating are superior to those of substrate, the surface strengthening effect is obvious.
2024 Vol. 29 (4): 263-274 [
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134
)
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206
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Engineering and Technology
275
Mechanical and ablation properties of 2D C
f
-ZrB
2
-SiC composites prepared by slurry brushing-hot pressing method
LI Tianyou, ZENG Yi, HU Jinrun, YI Bochao, GAO Meng
DOI: 10.19976/j.cnki.43-1448/TF.2024044
Continuous carbon fiber reinforced ZrB
2
-SiC composites have attracted much attention in the field of thermal protective structural materials for space vehicles due to their excellent oxidation and ablation resistance. In this paper, 2D C
f
-ZrB
2
-SiC composites were prepared by the slurry brushing-hot pressing method, the feasibility of using micron-sized powder slurry to prepare 2D C
f
-ZrB
2
-SiC composites was explored, the effects of sintering temperatures on the microstructure and mechanical properties of the materials were investigated, and the ablation resistance of the materials was tested. The results show that the 2D C
f
-ZrB
2
-SiC composite prepared by micron-sized powder slurry brushing-hot pressing method has the highest density and flexural strength after sintering at 2 000 ℃, with an open porosity of 8.01% and a flexural strength of 191.3 MPa; it appears good ablation resistance, the surface response temperature reaches 2 600 ℃, and the linear ablation rate is 3.51 μm/s after plasma flame ablation for 300 s.
2024 Vol. 29 (4): 275-289 [
Abstract
] (
90
)
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184
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290
Electric field assisted dynamic hot forging preparation of 3YSZ ceramic with ultrahigh toughness
ZHANG Botao, YAO Shu, FAN Jianye, ZHAO Ke, LIU Jinling, LIU Dianguang
DOI: 10.19976/j.cnki.43-1448/TF.2024032
The inherent brittleness greatly limits the wide application of high performance ceramic materials in the industrial field. In this paper, ultrahigh toughness 3YSZ ceramics were prepared by electric field assisted dynamic hot forging. The microstructure evolution and mechanical properties of 3YSZ ceramics under the coupling of electric field and dynamic force field were studied. The results show that: under the conditions hot forging for 10 min at a constant furnace temperature of 1 000 ℃, electric field strength of 20 V/cm, current density of 140 mA/mm
2
, and dynamic pressure of (50±10) MPa, the Vickers hardness and fracture toughness of 3YSZ ceramic reache (12.40±0.58) GPa and (10.69±0.33) MPa·m
1/2
, respectively, which increase 11.5% and 54.9% compared with the conventional sintered ceramic. The remarkable improvement of toughness mainly due to the stability of the tetragonal phase in 3YSZ ceramics reduced by electric field assisted dynamic hot forging, which makes it easier to undergo phase transformation when induced by external force, so as to effectively inhibit crack propagation. Electric field assisted dynamic hot forging technology has the advantages of no need to add reinforcement phase and remarkable toughening effect, which provides a new path for toughening high performance 3YSZ ceramic materials.
2024 Vol. 29 (4): 290-297 [
Abstract
] (
129
)
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233
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298
Local corrosion behavior of ultra-high-strength aluminum alloys
ZHANG Qianqian, ZHU Mengzhen, CHEN Xubin, XU Yongxiang, HU Xiaoyu, FANG Huachan
DOI: 10.19976/j.cnki.43-1448/TF.2024047
Al-Zn-Mg-Cu alloys were prepared by the traditional melt casting method. The effects of recrystallization and crystalline phase on the corrosion behavior of Al-Zn-Mg-Cu alloys were investigated through intergranular, exfoliation, stress, and electrochemical corrosion experiments, combined with characterization means such as metallurgical microscopy, scanning electron microscopy, and transmission electron microscopy. The results show that the Al-Zn-Mg-Cu-Zr alloy with lower degree of recrystallization and fewer residual crystalline phases has better corrosion resistance, the grade of exfoliation corrosion after 48 h of corrosion is EB, the time of stress corrosion crack initiation with bending tensile stress of 522 MPa is 30 min, and the rate of electrochemical corrosion becomes slower. The corrosion of ultra-high-strength aluminum alloy has three stages: at the early stage, pitting corrosion occurs around the residual crystalline phase (S phase) and the grain boundary precipitate phase (η phase); at the middle stage, pitting corrosion develops into intergranular corrosion along the high-angle grain boundary, and cracks are formed in the vicinity of the S phase and expand along the high-angle grain boundaries, leading to stress corrosion cracking; at the late stage, the expansion of corrosion products as well as the combined effect of intergranular corrosion and stress corrosion cracking trigger the exfoliation corrosion. The residual crystalline phase and recrystallization have a detrimental effect on its corrosion performance, the residual S phase in the matrix provides a site for corrosion to occur, and the η phase is continuously distributed on the high-angle grain boundaries formed by recrystallization, which provides a continuous channel for the expansion of intergranular corrosion and stress corrosion cracking.
2024 Vol. 29 (4): 298-310 [
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177
)
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203
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311
In-situ reaction mechanism and joint microstructure and properties of CuSnTi composite brazing material
ZHAO Yijia, JIU Yongtao, LIU Hao, CHEN Zhengnan, DING Zongye, LU Quanbin
DOI: 10.19976/j.cnki.43-1448/TF.2024045
Simplifying the preparation process of CuSnTi solder and reducing production costs are crucial for the development of high-performance tools. In this paper, direct mechanical mixing technique of Cu, Sn, and Ti metal powders was employed to synthesize CuSnTi brazing materials, which was then used to brazed PcBN/YG8 heterogeneous materials. The evolution of microstructures of CuSnTi brazing materials at different reaction temperatures were studied, the in-situ reaction mechanism of brazing materials during the brazing process was revealed, and the microstructure and properties of joint were analyzed. The results show that the in-situ reaction of CuSnTi brazing material can be mainly divided into three stages: in the first stage, Sn melts and reacts with Cu to form Cu
6
Sn
5
and Cu
3
Sn in sequence; in the second stage, CuTi, Cu
4
Ti
3
, CuTi
3
, and CuSn
3
Ti
5
precipitate surrounding Ti particles in sequence; in the third stage, liquid brazing material reacts with graphite substrate leading to the formation of TiC, and then solidification and precipitation of irregular CuSn
3
Ti
5
. PcBN/YG8 joints brazed with mechanical mixed powder brazing material and alloy powder brazing material both have good metallurgical bonding, with shear strengths of 96.06 MPa and 91.40 MPa, respectively. The joint brazed with mechanical mixed powder brazing material breaks at the PcBN site and exhibits excellent mechanical properties.
2024 Vol. 29 (4): 311-319 [
Abstract
] (
105
)
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160
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320
Effects of deformation temperature on microstructure and mechanical properties of multi-directional forged 7050 aluminum alloy
HUANG Haowei, WANG Haijun, ZHANG Shuai, LI Huizhong, LIANG Xiaopeng, ZENG Zhiheng
DOI: 10.19976/j.cnki.43-1448/TF.2024050
Multi-directional forging tests with different deformation temperatures (390, 420, 450 ℃) were carried out on homogenized 7050 aluminum alloy ingots. The effects of deformation temperature on the microstructure and mechanical properties of forged, solution-treated, and aged 7050 aluminum alloy were investigated using optical microscope, scanning electron microscope, electron backscattered diffraction, transmission electron microscope, as well as room temperature tensile tests. The results show that multi-directional forging can reduce the amount of residual crystalline phases, the area fraction of residual phases decreases with the increase of deformation temperature. The core of the alloys basically represents as coarse initial grains, the extent of dynamic recrystallization rises with the increase of deformation temperature after multi-directional forging; the area fraction of residual crystalline phases decreases, and the content of sub-grains increases with the increase of deformation temperature after solid-solution treatment; the amount of nanoscale precipitated phase increases with the increase of deformation temperature after aging treatment. The strength of the aged alloy increases with the increase of the deformation temperature. When the deformation temperature is 450 ℃, the comprehensive mechanical properties of the alloy are the best. The yield strength is 496.7 MPa, the tensile strength is 555.1 MPa, and the elongation is 8.1%.
2024 Vol. 29 (4): 320-329 [
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100
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155
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330
Preparation and properties of magnetic metal cobalt/carbon microwave absorber powders
LI Ziqi, DING Xueke, CHEN Chuansheng
DOI: 10.19976/j.cnki.43-1448/TF.2024049
To overcome the drawbacks of high density and single-mode magnetic loss in magnetic metals, Co-based metal organic frameworks were prepared by precipitation method using Co salt and trimesic acid as raw material and organic ligand, respectively. Magnetic metal Co/C composite microwave absorber powders were synthesized through calcination, and the effects of calcination temperature on the morphology and microwave absorption properties of Co/C microwave absorbers were studied. The results show that calcination temperature significantly affect the morphology and properties of Co/C absorbers, uniformly dispersed particle structure and porous framework structures can be obtained after calcination at 500 ℃ and 600 ℃, respectively, while chain-like rod structures can be obtained at 700 ℃ and 800 ℃. The sample calcined at 800 ℃ exhibits the best electromagnetic wave absorption property, with a maximum reflection loss of -35 dB and an effective absorption bandwidth of 0.56 GHz at 13.76 GHz when the tested sample thickness is 4.5 mm. The improvement in microwave absorption property is attributed to multiple loss mechanisms (such as eddy current and exchange resonance), suitable electromagnetic parameters and attenuation constant, and the synergistic effect between the porous structure and various components.
2024 Vol. 29 (4): 330-340 [
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72
)
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(1334 KB) (
165
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