MATERIALS CHARACTERIZATION
·
2024
·
IF 4.8
Shuai Ma,Di Dong,Mengyao Zhang,Ye Gao,Zhuangzhi Wu,Dezhi Wang
W-Re-HfC alloys have been extensively applied in the field of high-temperature structural parts. To ensure high temperature reliability, it is essential to enhance creep resistance ability. In this study, the microstructures of forged W-Re-HfC alloys were adjusted using different heat treatment processes . The corresponding tensile creep properties were also measured at 2000 °C with 40 MPa. Furthermore, a possible creep fracture mechanism was also explored. The forged W-Re-HfC sample annealed for 2 h exhibited the best creep performances with a steady-state creep rate of 3.28 × 10 −6 and a creep life of 5.6 h. Generally, a larger grain size indicates a lower steady-state creep rate; however, the precipitation of carbides at the grain boundaries (GBs) deteriorates the bonding strength of interfaces, thus reversing the former trend. The dominant creep mechanism is diffusion creep , in which the voids nucleate perpendicular to the GBs, grow and connect into cracks, ultimately leading to fractures.
研究领域:
材料科学
·
金属学与热处理
·
高温结构材料
·
固态物理
·
力学性能
✓ 已验证
DOI
高影响因子
MACROMOLECULES
·
2020
·
IF 5.918
Sheng Wang,Songqi Ma,Qiong Li,Xiwei Xu,Binbo Wang,Kaifeng Huang,Yanlin liu,Jin Zhu
Vitrimers undergoing dynamic bond exchange enable reprocessing and recycle of thermosets. However, vitrimers are susceptible to creep, leading to their poor dimensional stability, which limits their applications. Here, a facile method via integration of metal complexes was utilized to address this issue, and cross-linked polyimine was selected as an example of vitrimer. Three different metal complexes were introduced into a polyimine vitrimer via a one-pot preparation involving the formation of metal complexes and cross-linking of polyimine. The addition of 0.5 mol % Cu2+ relative to imine bond reduced creep degree from 30% to 20% at 60 °C, and the creep resistance was enhanced with increasing Cu2+ content. Loading 5 mol % Cu2+ increased the initial creep temperature from 60 to about 100 °C and raised the Arrhenius activation energy (Ea) for stress relaxation from 52.3 to 67.7 kJ mol–1. The ability of different metal complexes to suppress creep followed the order of Fe3+ > Cu2+ > Mg2+, and the initial creep temperature reached around 120 °C for vitrimer with 5 mol % of Fe3+. Meanwhile, the polyimine–metal complex vitrimers still exhibited excellent reprocessing recyclability. Moreover, the introduction of coordination structures enhanced the thermal and mechanical properties, solvent, and acid resistance. Thus, metal coordination is an efficient approach to achieve high-temperature creep resistance, excellent thermal and mechanical properties, and chemical stability for vitrimers based on the Schiff base.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Hao Nan Qiu,Ji Lin,Li Xin Hou,Rui Xiao,Qiang Zheng,Zi Liang Wu
Various glassy hydrogels are developed by forming dense physical associations within the matrices, which exhibit forced elastic deformation and possess high stiffness, strength, and toughness. Here, the viscoplastic behaviors of the glassy hydrogel of poly(methacrylamide-co-methacrylic acid) are investigated by stress relaxation and creep measurements. We found that the characteristic time of stress relaxation of the glassy gel is much smaller than that of amorphous polymers. The varying hydrogen bond strength leads to a broad distribution of structural activation energies, which in turn affects the range of characteristic time. In the presence of water, the weak hydrogen bond associations are easily disrupted under applied strain, enhancing segmental mobility and reducing relaxation time in the preyield regime, while in the postyield regime, the relaxation time increases slightly since the chain stretching increases the energy barrier. In creep tests, the creep strain rate accelerates at the initial stage due to stress-activated segments and then decelerates as chains are extensively stretched. The stress required for structural activation during creep is much lower than the Young’s modulus of the gel, reflecting the poor structural stability. To further analyze the underlying mechanism of the glassy gel, a micromechanical model is established based on an extension on shear transformation zone theory. By incorporating a state variable for hydrogen bond density, this model can capture the intricate mechanical responses of glassy gels. Our findings reveal that glassy hydrogels are far from the thermodynamic equilibrium state, exhibiting rapid segment activation under external loading. This work provides insights to the dynamics and structural stability of glassy materials and can promote the design and applications of tough hydrogels.
研究领域:
材料科学
·
生物力学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER SCIENCE SERIES A
·
2023
·Vol. 64
·期 6
·641-652
·
IF 1
Caixia Zhao,Xu Yuan,Yang Sheng,Zou Guoxiang,Li Jinchun,Dai Junming,Pan Xiaodi
Abstract The novel flexible and resilient poly(butylene succinate- co -butylene oxybisbenzoic) esters were synthesized by a two-step reaction of esterification and polycondensation. The obtained copolyesters were characterized using gel permeation chromatography, 1 H NMR spectroscopy, wide-angle X-ray diffraction, and dynamic thermomechanical analyzer. The mechanical properties were also investigated by the tensile, cyclic tensile, creep and recovery, and stress relaxation testing. The copolyesters have the amorphous nature, excellent flexibility. The elongation at break lies in the range of 510–2870%. In addition, several theoretical models were used to describe the creep and recovery behavior of the copolyesters for a better understanding of the mechanisms.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
Polymer Chemistry
·
2022
·Vol. 13
·期 28
·4144-4153
·
IF 5.364
Lin Wang,Yingjun Liu,Yunhe Qiao,Yuli Wang,Ziwen Cui,Shaoyi Zhu,Fuwei Dong,Sikun Fang,Aihua Du
It is very challenging to prepare elastomer vitrimers that are both robust and dimensionally stable in service. To address this issue, we have initiated a multi-phase design of elastomer vitrimers by incorporating quadruple hydrogen bonds (H-bonds) into vitrimer networks. Specifically, commercialized styrene–butadiene rubber (SBR) was functionalized with the synthesized 5-benzyl-3,6-dioxo-2-piperazineacetic acid (DKP) to introduce amide functionalities, which was then crosslinked by dimercapto-borate via thiol–ene “click” chemistry. The H-bonds between amide moieties functioned as sacrificial units, which could undergo reversible breakage and recombination events, and therefore improve the modulus, ultimate strength, and toughness simultaneously. Moreover, with an aromatic ring and a symmetrical amide group in the structure, the grafted DKP could self-assemble via hydrogen bonds, leading to the formation of a microphase-separated structure in the elastomer matrix. Besides, the creep resistance was improved as the H-bonds were physical crosslinks that imposed additional constraints on chain segment diffusion. Nevertheless, the reprocessability of the network was not affected as the H-bonds and boronic ester crosslinks could dissociate and exchange at elevated temperatures, respectively.
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 Chemistry Frontiers
·
2022
·Vol. 6
·期 4
·503-511
·
IF 8.683
Jinshi Han,Yawei Zhou,Guanghang Bai,Wei Wei,Xiaoya Liu,Xiaojie Li
Thermoset polyurethanes have been applied in various fields by virtue of their outstanding properties. However, the thermosets cannot be recycled due to their permanent crosslinking structure, which exerts a detrimental influence on the environment. Recently, the upsurge in the field of covalent adaptable networks (CANs) has attracted tremendous attention. Despite many efforts being dedicated to the design of CANs, the creep resistance of CANs holds much room for further improvement at high temperature. Here, we designed a kind of azine chain extender and prepared a series of dynamic polyurethane networks in varying azine proportions. The azine-containing CANs possess high creep temperature of ∼100 °C attributed to the stability of the azine moieties. Besides, the azine-containing polyurethanes also exhibit outstanding mechanical properties and reprocessability due to the conjugated structure and exchangeability of the azine moieties. The azine-containing polyurethanes also present good antibacterial properties as the azines are a special category of Schiff base. This work demonstrated that azine moieties could enhance the creep resistance, which is a long-term and crucial issue for dynamic covalent polyurethanes and endows the dynamic covalent polyurethane networks with excellent mechanical properties and intrinsic antibacterial properties.
研究领域:
材料科学
·
聚合物化学
·
可持续材料
✓ 已验证
DOI
高影响因子
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2021
·
IF 5.234
Cheng Zhang,Jilai Xue,Xuan Liu,Haipeng Li,Zengjie Wang,Xiang Li,Ying Liu
The deformation and structure stability of graphite cathodes are of importance for its service lifetime. The time dependence and coupling of deformation, elastoplastic property change and microstructure evolution of graphite cathodes were investigated under constant pressure at 940 °C. The deformations from early expansion transiting to the rapid and latter steady creep were found with increased hardness and modulus, in parallel with decreasing interplanar spacing of graphite (002) planes ( d 002 ) and increasing crystallite size along c -axis of graphite lattice ( L c ). The inner fracture among (002) planes may be related to the kink bands structure in graphite. It is clarified that no Na–C intercalation compounds get involved in change of graphite lattice. The crystallite size along a -axis ( L a ) can play an important role in structure stability with deformation-hardening effect on elastoplastic property and pinning effect on creep resistance. The deformation mechanism and the influencing factors on long-term structure stability of graphite cathode are also discussed in detail.
研究领域:
材料科学
·
固体力学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 22
·11261-11274
·
IF 11.301
Xiwei Xu,Songqi Ma,Sheng Wang,Jiahui Wu,Qiong Li,Na Lu,Yanlin Liu,Jintao Yang,Jie Feng,Jin Zhu
Covalent adaptable networks (CANs) provide a promising approach to solve the issue of recycling thermosets due to their dynamic cross-linked networks. However, CANs are susceptible to creep at relatively low temperatures, and their chemical stability is also inevitably doubtful. Here, we designed novel dihydrazone CANs by cross-linking a dihydrazone-containing epoxy monomer, which was synthesized from the condensation of a lignin derivative vanillin and hydrazinium hydrate, followed by a reaction with epichlorohydrin. Besides the excellent malleability and reprocessability, the dihydrazone CANs exhibited a high initial creep temperature of ∼105 °C, which was ascribed to the superior stability of the hydrazone bond at around 100 °C and favorable hydrazone exchangeability at elevated temperatures. Meanwhile, the degradation of the dihydrazone CANs exhibited temperature, solvent, and acidity dependence. Moreover, on account of the high antibacterial properties of the hydrazone bond, the CANs presented a high killing rate (95.8%) for Gram-negative bacteria (E. coli). Thus, this work discloses an effective dynamic covalent motif for the development of CANs with excellent dimensional stability, chemical resistance, and intrinsic antibacterial properties.
研究领域:
材料科学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Letters
·
2024
·
IF 8.6
Yang Zhao,Xiaobin Lin,Xudong Rong,Xiang Zhang,Dongdong Zhao,Chunnian He,Naiqin Zhao
Aluminum matrix composites (AMCs) reinforced with intragranular nano-sized Al2O3 were used as model material to investigate the effects of intragranular nano reinforcement on the mechanical properties at macro- and meso- levels. The results revealed that intragranular Al2O3 effectively facilitates the dislocation multiplication, which in turn enables the grain interior to endure high levels of plastic strain and consequently alleviates stress concentration at the grain boundary. Furthermore, intragranular Al2O3 leads to a collective enhancement in the intrinsic mechanical properties across domains of varying sizes, thereby contributing to the coordinated plastic deformation of heterogeneous grains, and enhancing the creep resistance of composite.
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2017
·
IF 4.873
Congmei Lin,Qiang Tian,Keping Chen,Guansong He,Jianhu Zhang,Shijun Liu,László Almásy
In this research, a group of segmented polyurethane (PU) copolymers with different hard segment (HS) contents were successfully synthesized. The microstructure of the PU copolymers was characterized via Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and small-angle neutron scattering (SANS). Then, the PU copolymers were selected as polymer binder for coating an insensitive high explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) to prepare polymer bonded explosives (PBXs). When the HS concentration of PU copolymers increased from 14 to 34 wt %, a 14.6 times increase in the creep rupture time of PBXs under 60 °C/3 MPa and a 52.3% decrease in the steady-state creep strain rate under 60 °C/1 MPa were observed. The experimental results indicated that a wide variety of structure and properties of PU copolymer could be customizable through the adjustment of the HS contents, and consequently, provided an efficient route to tune the creep performance of the PBXs over a wide range.
研究领域:
材料科学
·
爆炸物工程
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2023
·Vol. 20
·期 3
·1646-1657
·
IF 2.1
Lu Fu,Shifeng Wen,Wanbo Hou,Xinhao Shi,Tao Feng,Mingde Tong
2D-C/HfC–SiC composites were prepared by a combination of precursor infiltration and pyrolysis (PIP) and chemical vapor infiltration (CVI). Creep tests were performed at 1100°C in air under different stress conditions. Unlike most, C/SiC and SiC/SiC ceramic matrix composites only underwent primary and secondary creep stages, and the C/HfC–SiC composites underwent tertiary creep stage in the creep process. The reason was that the mechanical properties of C/HfC–SiC materials prepared by PIP + CVI methods were different from those prepared by traditional methods. The microscopic morphological analysis of the sample fracture showed that the oxidation products SiO 2 and Hf–Si–O glass phases of the HfC–SiC matrix played a crack filling role in the sample during creep. In turn, it provided effective protection to the internal fibers of the sample. The creep failure of C/HfC–SiC composites in a high-temperature oxidizing atmosphere was caused by the oxidation of the fibers. The total creep process was dominated by the oxidation of carbon fibers. It is noteworthy that there was the generation of Hf x Si y O z nanowires in the samples after high-temperature creep. The analysis of the experimental data showed that the creep stress had a linear negative correlation with the creep life.
研究领域:
材料科学
·
力学
✓ 已验证
DOI
高影响因子
Science Advances
·
2025
·Vol. 11
·期 11
·
IF 12.5
Jia Song,Rusong Yang,Junli Shi,Xingxing Chen,Sai Xie,Zelong Liao,Ruijie Zou,Yupeng Feng,Terry Tao Ye,Chuan Fei Guo
The real-time monitoring of health conditions of humans is a long-lasting topic, but there are two major challenges. First, many biomedical applications accept only implanted sensors. Second, tissue-like soft sensors often suffer from viscoelasticity-induced signal drift, causing inaccurate measurements. Here, we report a wireless and drift-free sensory system enabled by a low-creep polyelectrolyte elastomer. The system consists of the iontronic pressure sensors incorporating inductance-capacitance (LC) oscillators, exhibiting combined low drift ratio, high Q factor, high robustness to interferences, and wide-range measurement, superior to other capacitive sensors using regular dielectrics or ionogels. We have recorded 14-day orthodontic loads of two subjects using the system, showing pressure decreasing from 300 to 50 kPa and torque from 12.5 to 0.5 N·mm. The wireless, drift-free sensory system may be extended to other implants for long-term and accurate sensing.
研究领域:
生物医学工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）