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Quasi-plastic deformation mechanisms and inverse Hall-Petch relationship in nanocrystalline boron carbide under compression

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Chinese Physics B 2024年第8期33卷 405-413页

作者：岳珍李君刘立胜梅海 Hubei key laboratory of Theory and application of advanced materials Mechanics Wuhan University of TechnologyWuhan 430070China

Grain boundaries(GBs)play a significant role in the deformation behaviors of nanocrystalline ***,we investigate the compression behaviors of nanocrystalline boron carbide(nB_(4)C)with varying grain sizes using molecular dynamics simulations with a machine-learning force *** results reveal quasi-plastic deformation mechanisms in nB_(4)C:GB sliding,intergranular amorphization and intragranular *** sliding arises from the presence of soft GBs,leading to intergranular *** amorphization arises from the interaction between grains with unfavorable orientations and the softened amorphous GBs,and finally causes structural ***,nB_(4)C models with varying grain sizes from 4.07 nm to 10.86 nm display an inverse Hall-Petch relationship due to the GB sliding mechanism.A higher strain rate in nB_(4)C often leads to a higher yield strength,following a 2/3 power *** deformation mechanisms are critical for the design of ceramics with superior mechanical properties.

关键词： nanocrystalline boron carbide compression grain boundary sliding amorphization inverse Hall–Petch behavior

Surface vitrification of carbon by laser treatment: Insights of glass formation from molecular dynamics

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Journal of advanced Ceramics 2024年第6期13卷 729-735页

作者： Yanhui Zhang Haifeng Yu Yongying Jia Zhisheng Zhao Li-Min Wang Riping Liu Center for advanced structural materials State Key Laboratory of Metastable Materials Science and TechnologyYanshan UniversityQinhuangdao 066004China

Microstructural modification of carbon materials,such as carbon fibers(Cf)and pyrolytically deposited carbon,is important for engineering ***,the regulation of these materials is not an effortless *** understand the impacts of thermal spikes from pulsed laser processing on the structural adaptation of amorphous carbon(a-C),we performed melt quenching by molecular dynamics(MD)*** results confirm that the vitrification behavior of carbon can be tuned by adjusting the cooling rate(R),which is controlled by the thermal spikes of laser ***,we set up a two-step way to locate the critical cooling rate(R_(c))of monoatomic carbon,which is refined by the sharp change in the environmental similarity *** this novel technique,we demonstrate that the ordering degree and the local atomic motif can be largely modified by going across a bar of 100 K/ps,which is extracted as the critical cooling rate to ensure the complete amorphization of *** approach provides a criterion for both experimentally processing and theoretically simulating a-C ***,this work provides guidelines on how to tune the amorphous carbon structures of engineering materials and provides an outlook for the wonderland of amorphous carbon materials.

关键词： molecular dynamics(MD) structural order carbon fibers(Cf) vitrification critical cooling rate(R_(c))

Persistent radical anion of perylene dianhydride:an emerging metal-free photocatalyst for near-infrared photocontrolled RAFT polymerization

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Science China Chemistry 2024年第2期67卷 677-686页

作者： Haitao Zhao Guoqing Bian Xiang Xu Weiwei He Lifen Zhang Zhenping Cheng State and Local Joint Engineering laboratory for Novel Functional Polymeric materials Jiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationSuzhou Key Laboratory of Macromolecular Design and Precision SynthesisCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou215123China

Developing a new type of photocatalyst(PC) and catalytic mechanism for near-infrared(NIR) photocontrolled reversibledeactivation radical polymerization(RDRP) system is charming but ***,a novel PC of the persistent radical anion(PRA)(possessing the properties of both radical and anion) was developed for NIR photocontrolled reversible additionfragmentation chain transfer(RAFT) polymerization,enabling successful polymerization while gaining a deep insight into the mechanism of photo-induced electron transfer RAFT(PET-RAFT) *** from the conventional and wellaccepted reductive quenching(RQ) pathway,in which the radical anion intermediates of PCs(PCs^(·-)) must be generated in an excited state(ES),here,the PRA(3,4,9,10-perylenetetracarboxylic dianhydride radical anion(PTCDA^(·-))) could generate conveniently in situ in the ground state(GS) and subsequently serve as highly efficient PC in the NIR region(740–850 nm).The successful implementation of this strategy elucidates the peculiar role played by light and the real way of electron transfer *** fact,the transfer of a single electron from PRA to chain transfer agent(CTA) and cleavage of the C–S bonds is a process from ES to GS,rather than always from GS(PCs^(·-)) to GS(CTA) in the RQ pathway as is well known to *** addition,the excellent spatial-temporal control and powerful penetration ability of the NIR light were also confirmed by this PRAcatalyzed polymerization system.

关键词： photocatalyst persistent radical anion(PRA) near-infrared(NIR)light reversible-deactivation radical polymerization(RDRP) photo-induced electron transfer RAFT(PET-RAFT)polymerization

Designing gradient nanograined dual-phase structure in duplex stainless steel for superior strength-ductility synergy

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Journal of materials Science & Technology 2024年第3期170卷 122-128页

作者： Songsong Xu Ying Han Jiapeng Sun Guoqing Zu Mingkun Jiang Weiwei Zhu Xu Ran key laboratory of advanced structural materials Ministry of EducationChangchun University of TechnologyChangchun 130012China School of materials Science and Engineering Changchun University of TechnologyChangchun 130012China Provincial key laboratory of advanced materials Processing and application for Rail Transit Changchun University of TechnologyChangchun 130012China College of Mechanics and materials Hohai UniversityNanjing 211100China

Similar to other metallic materials,duplex stainless steel dramatically loses its advantage of high ductility as they are ***,we produce a gradient nanograined dual-phase structure in the 2101 duplex stainless steel,thus facilitating a superior strength-ductility synergy:a yield strength of 1009.5 MPa being two times higher than that of the as-received sample,a total elongation of 23.4%and a uniform elongation of 5.9%.This novel structure is produced through a processing route of ultrasonic severe surface rolling and annealing,which realizes a superposition of gradient nanostructure and lamellar dual-phase structure with austenite and *** the tension deformation of gradi-ent nanograined dual-phase structured duplex stainless steel,a significant accumulation of geometrically necessary dislocations *** dislocations are formed to accommodate the deformation incompat-ibility caused by the layer-by-layer difference in strength and hardness of individual phase domains,as well as the inherent difference in properties between the austenite and ferrite *** results in a stronger hetero-deformation induced strengthening and hardening significantly contributing to superior mechanical *** study provides a new avenue to develop advanced steels with high strength and ductility.

关键词： Gradient structure Duplex stainless steel Synergetic strengthening Strength Ductility

Combination of High Yield Strength and Improved Ductility of 21Cr Lean Duplex Stainless Steel by Tailoring Cold Deformation and Low-Temperature Short-Term Aging

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 695-702页

作者： Zhenghong Liu Zhigang Wu Ying Han Xiaolei Song Guoqing Zu Weiwei Zhu Xu Ran key laboratory of advanced structural materials Ministry of EducationChangchun University of TechnologyChangchun130012China School of materials Science and Engineering Changchun University of TechnologyChangchun130012China Jilin Province key laboratory of advanced materials Processing and application for Rail Transit Changchun University of TechnologyChangchun130012China

Proper matching of cold-rolled deformation and low-temperature short-term aging can simultaneously enhance the strength and ductility of the lean duplex stainless steel. To investigate this, the microstructure evolution of cold-rolled and aging steels was observed by using scanning electron microscopy, transmission electron microscopy and electron backscattered diffraction. Additionally, the phase volume fraction was measured using X-ray diffraction. In this study, it was observed that the elongation of 21Cr lean duplex stainless steel significantly increased to 16.7% after undergoing moderate cold deformation (~ 40% reduction) and subsequent aging treatment at 550 ℃ for 30 min. Remarkably, the material still maintained a high yield strength of 1045 MPa. Such an excellent mechanical property was attributed to a unique microstructure combination of fine α'-martensite, twins, coarsened austenite resulting from partial martensite reverse transformation, and two-phase fine layered structure. The result of this study may open up new horizons for the alloy development in order to overcome the low ductility of cold-rolled high-strength lean duplex stainless steel.

关键词： Lean duplex stainless steel Cold rolling Aging Microstructure Mechanical properties Use our pre-submission checklist

Piperazine-Assisted Construction of 2D/3D Wide-Bandgap Perovskite for Realizing High-Efficiency Perovskite/Organic Tandem Solar Cells

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Chinese Journal of Chemistry 2024年第16期42卷 1819-1827页

作者： Ziyue Wang Shuaiqing Kang Xia Zhou Haiyang Chen Xingxing Jiang Zhichao Zhang Jialei Zheng Ruopeng Zhang Weijie Chen Jiandong Zhang Yaowen Li laboratory of advanced Optoelectronic materials Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and DevicesCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhouJiangsu 215123China jiangsu key laboratory of advanced Negative Carbon Technologies Soochow UniversitySuzhouJiangsu 215123China State and Local Joint Engineering laboratory for Novel Functional Polymeric materials Jiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhouJiangsu 215123China College of Physics and Electronics Engineering Hengyang Normal UniversityHengyangHunan 421002China

Monolithic perovskite/organic tandem solar cells(TsCs)have gained significant attention due to their easy device integration and the potential to surpass the Shockley-Queisser limit of single-junction solar ***,the surfaces of wide-bandgap perovskite films are densely populated with defects,leading to severe non-radiative recombination and energy *** a consequence,the power conversion efficiency(PCE)of perovskite/organic TSCs lags behind that of other TSC *** address these issues,we designed a functional ammonium salt,4-(2-hydroxyethyl)piperazin-1-ium iodide(Pzol),comprising a piperazine iodide and a terminated hydroxyl group,which was applied for post-treating the perovskite *** findings reveal that Pzol reacts with and consumes residual PbX_(2)(X:I or Br)to form a 2D perovskite component,thereby eliminating Pb^(0)defects,while the terminated hydroxyl group in PZOI can also passivate uncoordinated Pb^(2+).Consequently,the shallow/deep-level defect densities of the 2D/3D perovskite film were significantly reduced,leading to an enhanced PCE of single-junction 2D/3D wide-bandgap perovskite solar cells to 18.18% with a reduced energy loss of 40 ***,the corresponding perovskite/organic TSCs achieved a remarkable PCE of 24.05% with enhanced operational stability(T_(90)~500h).

关键词： Perovskite/organic tandem solar cell Defect states Piperazine ion salt Energy conversion Low-dimensional materials Perovskitesolar cells 2D/3D perovskites Efficiency

Enhanced charge collection of AgNWs-based top electrode to realize high-performance,all-solution processed organic solar cells

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Science China Chemistry 2024年第10期67卷 3347-3356页

作者： Juanyong Wan Yang Chen Weijie Chen Jinfeng Xia Guang Zeng Jianlei Cao Chuang Jin Yunxiu Shen Xiaoxiao Wu Haiyang Chen Junyuan Ding Xue-mei Ou Yaowen Li Yongfang Li laboratory of advanced Optoelectronic materials Suzhou Key Laboratory of Novel Semiconductor-Optoelectronics Materials and DevicesCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China jiangsu key laboratory of advanced Negative Carbon Technologies Soochow UniversitySuzhou 215123China State and Local Joint Engineering laboratory for Novel Functional Polymeric materials Jiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China Beijing National laboratory for Molecular Sciences CAS Key Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China jiangsu Sidike New materials Science and Technology Co. Ltd.Suqian 215400China

All-solution processed organic solar cells are the ultimate aim of printable photovoltaics,but their electrical losses arising from poor contact of top electrodes greatly limit efficiency *** solve the problem,a solution-processed hybrid top electrode was constructed using silver nanowires(AgNWs)as the skeleton and ZnO nanoparticles(ZnO-NPs)as the *** constructing the skeleton,a spin-rinsing treatment was first used to reduce the amount of the residual insulating polyvinylpyrrolidone wrapped around the AgNWs to promote intimate contact among the AgNWs in the ***,the ZnO-NPs matrix was deposited onto the AgNWs skeleton,bridging the AgNWs skeleton with the underlayer ZnO-NPs electron transporting layer(ETL).The underlayer ZnO-NPs ETL can also induce the growth of the ZnO-NPs matrix to minimize lattice mismatch,which creates additional transport channels from the ETL to the AgNWs skeleton for charge *** a result,the obtained electrode significantly enhances the electrical contact in the device,thus delivering record power conversion efficiencies of 16.04%and 14.54%for rigid and flexible all-solution processed OSCs,respectively.

关键词： solution-processed top electrode organic solar cells AgNWs electrical contact

Effect of Composite Composition on the Contact Angle of B_(4)C-xTiB_(2)/Cu

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Journal of Wuhan University of Technology(materials Science) 2024年第5期39卷 1116-1120页

作者： HU Dong ZHANG Xin ZHANG Jinyong LEI Liwen State key laboratory of advanced Technology for materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Hubei key laboratory of Theory and application of advanced materials Mechanics Wuhan University of TechnologyWuhan 430070China

The wetting behavior of molten Cu on the B_(4)C-xTiB_(2)ceramic composites was investigated in this *** results show that the contact angle of molten Cu alloy on B_(4)C-TiB_(2)ceramic composites is linear with the composition rate of TiB_(2)or B_(4)C while the temperature is in the range of 1300 to 1350℃,consistent with the expectation of the commonly used theoretical ***,a nonlinear relationship between the contact angle and the composition rate unexpectedly occurred at temperatures ranging from 1400 to 1500℃.The big difference of the contact angles between the molten metal and the components in the composites was found to be the key *** result identifies that the commonly used theoretical method only works at a limited difference of the contact angle of the liquid on the different phases in the composites,and fails at a big difference.

关键词： wetting B_(4)C-TiB_(2) composites interfacial reaction

Enhanced Grain Refining Effect of Mg–Zr Master Alloy on Magnesium Alloys via a Synergistic Strategy Involving Heterogeneous Nucleation and Solute‑Driven Growth Restriction

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Acta Metallurgica Sinica(English Letters) 2024年第8期37卷 1354-1366页

作者： Gang Zeng Hong Liu Jing‑Peng Xiong Jian‑Long Li Yong Liu key laboratory of Lightweight and High Strength structural materials of Jiangxi Province School of Advanced ManufacturingNanchang UniversityNanchang 330031China

Zirconium(Zr)emerges as the most effective grain refiner for magnesium(Mg)alloys incorporating ***,Zr is introduced in the form of an Mg–Zr master ***,within Mg–Zr master alloys,Zr predominantly exists in a particle form,which tends to aggregate due to attractive van der Waals *** clustered Zr is prone to settling,thereby reducing its refining impact on Mg *** this work,a combined pretreatment process for Mg–Zr master alloys was proposed,encompassing the introduction of a physical field to intervene the agglomeration of particle Zr and the employ of high-temperature dissolution and peritectic reactions to promote the solid solution of *** results demonstrate that the particle Zr within the pretreated Mg–Zr master alloy is effectively dispersed and refined,and greater solute Zr levels can be *** subsequent grain refinement ability was studied on a typical Mg–6Zn–0.6Zr(wt%)*** outcome highlights that an improvement in the grain refinement efficacy(32.4%)of Mg–Zr master alloys was obtained with a holding time of 60 *** pretreated Mg–Zr master alloy significantly augments the efficiency of grain refinement for Mg alloys through a synergistic strategy involving heterogeneous nucleation and solute-driven growth *** crucial factor in achieving effective grain refinement of Zr in Mg alloys lies in regulating the presence and morphology of Zr in the Mg–Zr master alloy,distinguishing between particle Zr and solute *** study introduces a novel method for developing more efficient Mg–Zr refiners.

关键词： Magnesium alloy Mg-Zr master alloy Grain refinement Heterogeneous nucleation Solute-driven growth restriction Synergistic strategy