TRANSPORT IN POROUS MEDIA
·
2021
·Vol. 144
·期 1
·133-148
·
IF 3.019
Dai Caili,Chu Zhongzhong,Jiang Qihui,Wu Yining,He Long,Zhao Mingwei
Polymer solution has extremely extensive applications in many natural and industrial processes, especially in oilfield development field, such as polymer flooding, fracturing and water shut-off. Thus, the study of flow behaviors of polymer in formation pores is significantly important. In this paper, the flow behaviors of the polymer droplets in the 3-D pore throat structure were systematically studied. Additionally, the influencing factors (polymer concentration, molecular weight and pore throat ratio, for instance) were investigated. As the increasing of polymer concentration and molecular weight, the polymer droplets were more difficult to break, which means the critical flow rate decreased and the average sizes of the first daughter droplets (FDD) were longer synchronously. Moreover, with the increase in pore throat ratio, the critical flow rate increased and the length of the FDD decreased. In addition, the prediction models of the length of the FDD with polymer concentration and pore throat ratio were established, respectively. The prediction model revealed that the length of the FDD satisfied an exponential relationship with the polymer concentration and a linear relationship with the pore throat ratio. Finally, the average size of droplets after macroscopic core flooding experiment was 8 μm and 17 μm when the polymer concentration was 0.01% and 0.1%, respectively. The results were consistent with the breakup behaviors of polymer droplets in the microscopic pore throat structure.
研究领域:
石油工程
·
流体力学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2017
·
IF 5.835
Qingsong Lian,Yan Li,Kai Li,Jue Cheng,Junying Zhang
The vulcanization mechanism remains unclear due to the difficulty of characterization and the complexity of the vulcanization systems. In this work, a series of epoxy model systems were used to study the sulfur cleavage behavior, from which the study process of the vulcanization mechanism was significantly simplified and a brand new sulfur-only vulcanization mechanism was revealed by the FTIR and DSC analysis. Our studies suggest that thiyl radicals derived from the homolytic cleavage of sulfur play the dominant role in the vulcanization, while the heterolytic fission of sulfur cannot occur as expected because this reaction needs 200 °C. Nevertheless, sulfur anions, which are easy to be understood derived from the heterolytic cleavage of sulfur, are actually transformed from the thiol groups that are produced through the reaction of thiyl radicals abstracting α-H atoms of allyl groups in rubber, and this maybe the reason that vulcanization mechanism remains controversial for centuries.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Materials Today Physics
·
2020
·
IF 10.443
S.Y. Zheng,H.C. Yu,C. Yang,W. Hong,F. Zhu,J. Qian,Z.L. Wu,Q. Zheng
The rapid developments of tough hydrogels have broadened the applications of gel materials in biomedicine and engineering fields, which recalls the fundamental understanding of the fracture behaviors of these tough, soft materials. Herein, we study the fracture behaviors of a Fe 3+ coordinated poly(acrylic acid- co -acrylamide) (P(AAc- co -AAm)) hydrogel through pure shear tests. We measure a material-specific length, called fractocohesive length L f , defined by the ratio of fracture energy to fracture work ( L f = Г / W f ). We show that L f scales several important lengths that characterize the fracture behaviors of the hydrogel, including the transition length of cut-sensitivity L c measured by stretching samples of various initial crack lengths to rupture, the increment of the crack length needed to attain the steady state L ss measured from the resistance curve, and the size of large deformation zone L i measured by the polarized microscopic image. We further show that the fracture of P(AAc- co -AAm) hydrogel is viscoelastic, as demonstrated by tensile and rheological tests at different deformation rates . This work gives an insight into the fracture behaviors of P(AAc- co -AAm) hydrogel and provides a methodology that should be applicable in characterizing the fracture behaviors of other tough materials.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·Vol. 107
·期 1
·404-416
·
IF 3.9
Wenhao Dou,Daxin Li,Bingzhu Wang,Delong Cai,Zhihua Yang,Dechang Jia,Ralf Riedel,Shaohua Qin,Yu Zhou
The layering process using phenolic resin coupled with pressureless sintering technique was explored to prepare short carbon fiber-reinforced SiBCN composites (C sf /SiBCN). The effect of phenolic resin content on the microstructure and mechanical properties of C sf /SiBCN was mainly studied. Results suggest that the addition of phenolic resin can appropriately improve density and flexural strength and reduce total pore volume of the composites because phenolic resin can partly consolidate SiBCN powders to promote shaping via low-temperature pressureless sintering. As the phenolic resin content increases, the fracture behavior changes from delamination fracture to monolithic fracture, thereby reducing fracture displacement. The reason for this performance is that the interlayer bonding is enhanced to hinder crack propagation along the layers.
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Yingxuan Chen,Hongzhi Cui,Leigang Li,Xiaojie Song,Yipan Feng,Cuiting Zhang,Wei Huang
Benefiting from the extraordinary mechanical properties especially at elevated temperatures, Ni625/WC composites have been regarded as promising structural materials for deep well drilling. However, the addition and formation methods of WC would effect the mechanical properties of the composites greatly. In this work, Ni625/WC composites by spark plasma sintering technique are investigated, and the influences of WC by the external adding method and the internal in-situ formation method on the morphology, friction and fracture behaviors of the materials are analyzed systematically. It is found that the samples with externally added WC as the reinforcing phase possess enhanced wear resistance because of the high hardness and embedding depth of the externally added large-size WC. The large hardness difference with the matrix and the high brittleness lead to serious adhesive wear and poor toughness of the samples. On the contrary, the samples with in-situ WC as the reinforcing phase have superior toughness owing to the tighter bonding of in-situ generated WC to the matrix, lower brittleness of tungsten carbide and slower propagation of cracks. This work, with the systematic and comparative study of the incorporation of WC to the influence of mechanical properties of Ni625/WC, would enlighten the design of advanced metal-ceramic composites to meet the specific requirements of different structural materials.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2016
·
IF 2.933
Xiaowu Chen,Shaoming Dong,Yanmei Kan,Xihai Jin,Haijun Zhou,Dewei Ni,Dengke Wang
Three-dimensional C f /SiC-ZrC-ZrB 2 composites were fabricated by reactive melt infiltration of ZrSi 2 alloys into porous C f /B 4 C-C preforms prepared through a sol-gel process. The influence of pore structure of the C f /B 4 C-C preforms on microstructure and mechanical performances of the C f /SiC-ZrC-ZrB 2 composites was studied. It was found that the microstructure and mechanical performances of the composites showed a strong dependence on the pore structure of the preforms. Residual ZrSi 2 content in the composites was significantly reduced with the decreases in the porosity and pore size of the C f /B 4 C-C preforms. At the same time, fiber erosion in the composites was also gradually mitigated, which led to a significant improvement in the fracture behaviors of the composite, as failure mode of the composites changed from brittle to pseudo-plastic. When the porosity of the preforms decreased from 53.7% to 31.3%, the flexural strength of the composites increased from 53 MPa to 184 MPa.
研究领域:
材料科学
·
复合材料工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Dongyang Zhang,Ping Hu,Shun Dong,Qiang Qu,Xinghong Zhang
The high sintering temperature and interface interaction seriously degraded the toughening effects of continuous carbon fiber in ZrB 2 -SiC ceramic. The pyrolytic carbon coated carbon fiber reinforced ZrB 2 -SiC composite (C f-PyC /ZrB 2 -SiC) with desirable properties was successfully achieved via brushing nano ZrB 2 -SiC slurry followed by spark plasma sintering at relatively low sintering temperature. The fabricated C f-PyC /ZrB 2 -SiC composite presented a non-brittle fracture feature and a remarkable enhancement in comparison with the ZrB 2 -SiC composite reinforced by the as-received carbon fiber (C f-AS /ZrB 2 -SiC). The fracture toughness and critical crack size were increased from 5.97 ± 0.18–7.66 ± 0.24 MPa m 1/2 and from 91.6 to 164.5 µm, respectively. A high work of fracture of 1915 J/m 2 for C f-PyC /ZrB 2 -SiC composite was achieved, almost four times higher than that of the C f-AS /ZrB 2 -SiC composite (463 J/m 2 ). Multiple toughening mechanisms contributed to such enhancement, such as crack deflection, fiber bridging, fiber pull-out and crack branching. This work provides a feasible approach to fabricate high-performance fiber reinforced ceramic composites having a high work of fracture.
研究领域:
材料科学
·
工程学
✓ 已验证
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2024
·Vol. 21
·期 5
·3302-3310
·
IF 1.8
Rongpei Wang,Gang Wang,Songlin Ran,Wei Wang,Yunlong Yang,Yu Zhao,Kaixuan Gui,Rujie He,Caiwang Tan
AlCoCrFeNi 2.1 eutectic high-entropy alloy was introduced to join C f /SiC composite by spark plasma sintering technique. The influence of holding times on microstructure, shear strength and fracture behavior of the joints was studied. When held for 7 min, the typical microstructure of the C f /SiC-AlCoCrFeNi 2.1 -C f /SiC joint was C f /SiC composite → CrSi 2 + FCC + Al 8 Cr 5 + graphite → CrSi 2 + FCC + Al 8 Cr 5 → CrSi 2 + FCC + Al 8 Cr 5 + graphite → C f /SiC composite. As the holding time extended, the Ni–Si and Fe–Si brittle phases in the joint gradually reduced, and the diffusion transition layer continued to thicken. The maximum joint strength was 23.9 MPa, which was obtained at 1450°C for 7 min. Analyzed by scanning electron microscopy and energy dispersive spectroscopy, the fracture modes of the joints joined at different holding times were all brittle fracture.
研究领域:
材料科学
·
工程学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Cuiyan Li,Guibiao Li,Haibo Ouyang,Jianfeng Huang,Xianghui Hou
Carbon fiber reinforced carbon matrix containing ZrC (C/C–ZrC) composites were prepared by hydrothermal deposition combined with carbothermal reduction. The submicron ZrC particles (100–300 nm) were dispersed in the matrix. The stress-strain curves of the composites presented a typical pseudo-plastic fracture behavior . The mass and linear ablation rates of the composites were 3.7 × 10 −3 g/s and 4.2 × 10 −3 mm/s, respectively. The formation of ZrO 2 glass layer reduced erosion of the composites in the ablation center. The continuous C–ZrC–ZrO 2 skeleton layer generated from the oxidation of ZrC can protect the composites from erosion at the ablation brim region. The obtained C/C–ZrC composites present a promising potential as ablation resistance materials.
研究领域:
材料科学
·
复合材料工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2017
·Vol. 135
·期 5
·45562
·
IF 1.86
Dawei Xu,Dingcai Wu,Tongbai Yu,Ruowen Fu
A facile method is developed to synthesize silicone-toughened unsaturated polyester (SUP-M) by monomer copolymerization of anhydrides and diols with hydroxyl-terminated silicone. The structures and molecular weights of the SUP-M resins were characterized by Fourier transform infrared spectroscopy and gel permeation chromatography, respectively. The gelation time and mechanical properties, including impact strength, flexural strength, and tensile strength, were investigated. The fracture behaviors were studied by scanning electron microscopy, and their glass-transition temperature and storage modulus were measured by dynamic mechanical analysis. The experimental results showed that the impact strength of SUP-M can be obviously improved through copolymerization with a small amount of silicone without decreasing its mechanical properties. The impact strength, flexural strength, and tensile strength of SUP-M-0.5 are as high as 12.5 KJ m −2 , 131 MPa, and 59 MPa, which are increased by 76.1%, 21.2%, and 6.7%, respectively, compared with those of unsaturated polyester. Impacts on SUP-M with low silicone content produce a large number of evenly and regularly distributed continuous narrow crack bands combined with many evenly distributed branching crazes, which are of great benefit in absorbing a large amount of impact energy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 45562.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHARACTERIZATION
·
2022
·
IF 4.537
Jianlong Chai,Yabin Zhu,Peng Jin,Tielong Shen,Lijuan Niu,Shufen Li,Minghuan Cui,Zhiguang Wang
SiC-Al 2 O 3 -ZrO 2 ceramic composite with heterointerfaces was prepared by hot pressing and irradiated with 1.2 MeV Si ions at room temperatures. The microstructural evolution and mechanical properties were investigated. The results showed that the phase transformation of zirconia revealed by GIXRD and TEM are associated with the accumulation of oxygen vacancies clusters originated by damage and the size of displacement cascades. Complete amorphization of SiC particles were observed at 5.5 dpa, and developed into collection band at 55 dpa due to the mixture of point defect clusters and extend defects at high damage level. The nanohardness and elastic modulus irradiation decreased with increasing of damage level. The fracture behavior of materials and relative mechanism under ion irradiation were discussed.
研究领域:
材料科学
·
核材料工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
·
2025
·
IF 6
Jincheng Lei,Yuan Gao,Shuai Xu,Linchun He,Zishun Liu
Current constitutive theories and fracture models face difficulties in capturing the extremely large deformation and fracture behaviors of hydrogels, because the structural and mechanical properties of the effective polymer network dominated in hydrogels are still unknown. In this study, we propose a periodic random network (PRN) method to construct the effective polymer network model of polyacrylamide (PAAm) hydrogel from the bottom up and reveal the effect of the effective polymer network on the extremely large deformation and fracture behaviors of PAAm hydrogels. It is surprising that the PRN models determined by only three parameters capture the extremely large deformation and fracture behaviors of PAAm hydrogel in uniaxial tension experiments very well. The PRN models measure that only about 20 % of monomers and crosslinkers form the effective network in the PAAm hydrogel samples in this work, and the mean monomer number of the effective chains in PAAm hydrogels deviates a lot from that estimated by the ideal network assumption. An anisotropic damage accumulation process of PAAm hydrogel under extremely large deformation before bulk fracture is predicted by PRN models, which has been observed in previous experiments but not explained. This is the fundamental cause that the Lake-Thomas model underestimates the intrinsic fracture toughness of PAAm hydrogels very much. This work provides an insightful method to measure the structural and mechanical properties of hydrogels.
研究领域:
材料科学
·
生物力学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）