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Unraveling the advantages of Pd/CeO_(2)single-atom catalysts in the NO+CO reaction by model catalysts

Nano Research 2023年第7期16卷 8882-8892页

作者： Qian Xu xingwang cheng Ningqiang Zhang Yi Tu Lihui Wu Haibin Pan Jun Hu Honghe Ding Junfa Zhu Yadong Li Department of Chemistry Tsinghua UniversityBeijing 100084China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029China College of Chemistry and Materials Science Anhui Normal UniversityWuhu 241002China

Selective catalytic reduction of NO by CO is challenging in environmental catalysis but attractive owing to the advantage of simultaneous elimination of NO and CO.Here,model catalysts consisting of Pd nanoparticles(NPs)and single-atom Pd supported on a CeO_(2)(111)film grown on Cu(111)(denoted as Pd NPs/CeO_(2)and Pd_(1)/CeO_(2),respectively)were successfully prepared and characterized by synchrotron radiation photoemission spectroscopy(SRPES)and infrared reflection absorption spectroscopy(IRAS).The NO+CO adsorption/reaction on the Pd_(1)/CeO_(2)and Pd NPs/CeO_(2)catalysts were carefully investigated using SRPES,temperature-programmed desorption(TPD),and IRAS.It is found that the reaction products on both model catalysts are in good agreement with those on real catalysts,demonstrating the good reliability of using these model catalysts to study the reaction mechanism of the NO+CO reaction.On the Pd NPs/CeO_(2)surface,N_(2)is formed by the combination of atomic N coming from the dissociation of NO on Pd NPs at higher temperatures.N_(2)O formation occurs probably via chemisorbed NO combined with atomic N on the surface.While on the single-atom Pd_(1)/CeO_(2)surface,no N_(2)O is detected.The 100%N_(2)selectivity may stem from the formation of O-N-N-O^(*)intermediate on the surface.Through this study,direct experimental evidence for the reaction mechanisms of the NO+CO reaction is provided,which supports the previous density functional theory(DFT)calculations.

关键词： NO+CO reaction Pd/CeO_(2) model catalysts reaction mechanisms

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Composition design of a novel Ti-6Mo-3.5Cr-1Zr alloy with high-strength and ultrahigh-ductility

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Journal of Materials Science & Technology 2022年第36期131卷 276-286页

作者： Kai Chen Qunbo Fan Jiahao Yao Lin Yang Shun Xu Wei Lei Duoduo Wang Jingjiu Yuan Haichao Gong xingwang cheng National Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China

The strength-elongation to fracture(εf)trade-off and low strain hardening rate have been a longstanding dilemma in titanium alloys.In this work,we innovatively manufactured a novel Ti-6Mo-3.5Cr-1Zr alloy via the introduction of a stress-induced strengthening phase into the material.Stress-inducedω(SIω)phase transformation was expected to replace theα''martensitic transformation that resulted in the low yield strength of titanium alloys.The obtained alloy exhibited an extremely high strain hardening rate of up to^1820 MPa.The true peak tensile strength andεfreached^1242 MPa and^40%,respectively.The intrinsic mechanisms underlying the simultaneous improvement of strength and ductility of the material were systematically investigated via in-situ and ex-situ characterizations.In-situ electron backscatter diffraction(EBSD)/digital image correlation(DIC)results showed that SIωphase transformation dominated the early stage of plastic deformation(1.5%–3%)and promoted the strain partitioning between the stress-induced bands andβmatrix.Subsequently,the formation of{332}βtwins andωtwins was observed via ex-situ EBSD.In-situ transmission electron microscopy results revealed that dislocation pile-up(DPU)occurred at the SIω/βinterface.The coupling effects associated with the transformation induced plasticity(TRIP),twinning induced plasticity(TWIP),and DPU mechanisms contributed to the enhanced strength andεfof the designed titanium alloy.

关键词： Titanium alloy Mechanical properties Phase transformation Twinning Strain partitioning

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Texture evolution and slip mode of a Ti-5.5Mo-7.2Al-4.5Zr-2.6Sn-2.1Cr dual-phase alloy during cold rolling based on multiscale crystal plasticity finite element model

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Journal of Materials Science & Technology 2022年第16期111卷 76-87页

作者： Duoduo Wang Qunbo Fan xingwang cheng Yu Zhou Ran Shi Yan Qian Le Wang Xinjie Zhu Haichao Gong Kai Chen Jingjiu Yuan Liu Yang National Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China Microstructure and Properties of Materials(IEK-2) Forschungszentrum JülichJülichGermany chengdu Advanced Metal Materials Industrial Technology Research Institute Co.Ltd Chengdu 610000China

The complex micromechanical response among grains remains a persistent challenge to understand the deformation mechanism of titanium alloys during cold rolling.Therefore,in this work,a multiscale crystal plasticity finite element method of dual-phase alloy was proposed and secondarily developed based on LS-DYNA software.Afterward,the texture evolution and slip mode of a Ti-5.5Mo-7.2Al-4.5Zr-2.6Sn-2.1Cr alloy,based on the realistic 3D microstructure,during cold rolling(20%thickness reduction)were systematically investigated.The relative activity of the■slip system in theαphase gradually increased,and then served as the main slip mode at lower Schmid factor({110}slip system showed an upward tendency,indicating the important role of the critical resolved shear stress relationship in the relative activity evolutions.Furthermore,the abnormally high strain of very fewβgrains was found,which was attributed to their severe rotations compelled by the neighboring pre-deformedαgrains.The calculated pole figures,rotation axes,and compelled rotation behavior exhibited good agreement to the experimental results.

关键词： Titanium alloy Multiscale crystal plasticity finite element model Texture evolution Slip mode

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Dynamic response and damage evolution of Zr-based bulk metallic glass under shock loading

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Journal of Materials Science & Technology 2021年第34期93卷 119-127页

作者： Yan Li xingwang cheng Zhaolong Ma Xuhai Li Meng Wang National Key Laboratory of Science and Technology on Materials under Shock and Impact School of Material Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Science and Technology on Shock Waves and Detonation Physics Laboratory Institute of Fluid PhysicsChinese Academy of Engineering PhysicsMianyang 621900.China

Dynamic response and damage evolution of Zr_(70)Cu_(13)Ni_(9.8)Al_(3.6)Nb_(3.4)Y_(0.2) bulk metallic glass(Zr-based BMG)under impact pressure ranging from 4.03 GPa to 27.22 GPa were studied.The Hugoniot Elastic Limit(HEL)and the spalling Strength(σ_(sp))were measured as 7.09 GPa and 2.28 GPa,and the curve of impact velocity(D)and particle velocity(u)were also obtained.Under the strain rate of~10^(5)s^(-1),local crystallization phenomenon was observed.As increasing the impact pressure,the failure mode of Zr-based BMG changed from spallation to fragmentation caused by the combination of spalling cracks and longitudinal cracks.Cone-cup structures were also observed in the internal spalling zone via nano-CT characterization.When increasing the impact pressure,the thickness of Zr-based BMG increased after impact and the remelting and cladding layers were also observed on the fracture surfaces.The fragments of the specimen were welded after impact due to the high temperature remelting,which causes plastic deformation of Zr-based BMG under shock loading.

关键词： Zr-based bulk metallic glass Shock loading Dynamic response Damage evolution

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非均质Mn分布对淬火-配分钢微观组织和力学性能的影响

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金属学报 2024年第1期60卷 69-79页

作者：张超熊志平杨德振程兴旺北京理工大学材料学院冲击环境材料技术国家级重点实验室北京100081 北京理工大学唐山研究院唐山063000

目前,基于非均质高温奥氏体来调控先进高强钢的组织和性能,引起研究学者的广泛关注。为进一步明晰合金元素非均质程度对组织和性能的影响,指导先进高强钢的设计,本工作采用以Mn配分的珠光体为初始组织的快速淬火-配分工艺,研究了奥氏体... 详细信息

目前,基于非均质高温奥氏体来调控先进高强钢的组织和性能,引起研究学者的广泛关注。为进一步明晰合金元素非均质程度对组织和性能的影响,指导先进高强钢的设计,本工作采用以Mn配分的珠光体为初始组织的快速淬火-配分工艺,研究了奥氏体化时间和温度对高温奥氏体中非均质Mn分布的影响规律,进一步探讨了微观组织和力学性能的演变。结果表明,高温奥氏体的Mn分布能够调控淬火过程的马氏体转变。当高温奥氏体继承了珠光体中富Mn渗碳体和贫Mn铁素体中的Mn分布时,淬火后可获得富Mn片状残余奥氏体与贫Mn马氏体板条构成的鬼珠光体组织。随奥氏体化保温时间的延长和温度的升高,高温奥氏体中Mn元素非均质程度减弱,导致鬼珠光体组织减少,块状残余奥氏体和粗大板条马氏体数量增多、且尺寸增大。随着保温时间的延长,屈服强度由于细晶强化的减弱而降低;均匀延伸率由于块状残余奥氏体的增多而升高,颈缩后的延伸率因块状残余奥氏体形成的脆性马氏体而降低。由于残余奥氏体和马氏体的含量随着奥氏体化工艺不发生改变,使得抗拉强度和断裂总延伸率也不发生变化。由此可见,通过改变奥氏体化的工艺参数,能够在保证高抗拉强度(约1700 MPa)和高断裂总延伸率(约20%)的基础上,实现对屈服强度和均匀延伸率的进一步调控。

关键词：非均质组织 Mn配分珠光体残余奥氏体高温奥氏体

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Structural Modification of Al65Cu16.5Ti18.5 Amorphous Powder through Annealing and Post Milling： Improving Thermal Stability

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Journal of Materials Science & Technology 2016年第12期32卷 1326-1331页

作者： Zhen Tan Lu Wang Yunfei Xue xingwang cheng Long Zhang School of Materials Science and Engineering Beijing Institute of Technology Beijing 100081 China National Key Laboratory of Science and Technology on Materials under Shock and Impact Beijing 100081 China Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

To improve thermal stability of the Al65Cu16.5Ti18.5 amorphous powder,structural modification of the amorphous powder was performed through annealing and post milling.Annealing above the crystallization temperature（Tx） not only induced nanoscale intermetallics to precipitate in the amorphous powder,but also increased Cu atomic percentage within the residual amorphous phase.Post milling induced the amorphization of the nanocrystal intermetallics and the formation of Cu9Al4 from the residual amorphous phase.Thus,a mixed structure consisting of amorphous phase and Cu9Al4 was obtained in the powder after annealing and post milling（the APMed powder）.The phase constituent in the APMed powder did not change during the post annealing,which exhibited significantly improved thermal stability in comparison with the as-milled amorphous powder.

关键词： Amorphous powder Thermal stability Heat treatment Mechanical alloying Transmission electron microscopy

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Mechanical(compressive)form of driving force triggers the phase transformation fromβtoω&α”phases in metastableβphase-field Ti-5553 alloy

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Journal of Materials Science & Technology 2021年第19期78卷 238-246页

作者： Tayyeb Ali Lin Wang xingwang cheng Huanwu cheng Ying Yang Anjin Liu Xuefeng Xu Zhe Zhou Zixuan Ning Ziqi Xu Xinhua Min School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Science and Technology on Materials Under Shock and Impact Beijing 100081China Beijing Center for Physical and Chemical Analysis Beijing 100089China Baosteel Special Materials CO.LTD Shanghai China

Most of the structural alloys’applications are under static,dynamic,and cyclic forms of loading.Ti-5553 alloy in the beta phase field is being investigated to confirm the mechanism of deformation and phase transformation upon quasi-static and dynamic compression.The Ti-5553 alloy was heat-treated at 900℃ (almost 50℃ above beta transus temperature)for one hour of soaking time followed by air quenching to achieve a fullyβphase field.After that,Dynamic compression(DC)by Split Hopkinson Pressure Bar(SHPB)and Quasi-static compression(QSC)were performed at a strain rate of~10^3)/s and 10^(-3)/s,respectively.Recovered specimens were thoroughly examined by using different tools,such as an Optical microscope(OM),Scanning electron microscope(SEM),High-resolution transmission electron microscope(HRTEM),and Electron backscatter diffraction(EBSD)to get the reliable data for justification of logical conclusions.It is found that the dominating mode of deformation was dislocation slip along with twinning({332})to some extent in both of QSC and DC,but sliding&spalling of the grain boundary is observed more in the former.Stress-induced phase transformation,i.e.,βtoα"andβtoω,took place in the grains saturated with dislocation slips,where the former transformation occurred simultaneously with{332}twinning,whileβtoωtransformation was completed when a set of two adjacent(110)_(β)planes covered±1/6th of the total separation distance between two(next to each other)(111)_(β)planes,by equal but opposite shear in(111)_(β)direction,and it caused 3%shrinkage of two closed packed(110)_(β)planes after transformation.

关键词： Quasi-static&dynamic compression Phase transformation Deformation structures Dislocation slips Grain boundary sliding

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基于“新工科”的《热处理原理与工艺》类课程教学内容改革

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金属热处理 2024年第4期49卷 284-287页

作者：熊志平王迎春程兴旺北京理工大学材料学院冲击环境材料技术国家级重点实验室北京100081

《热处理原理与工艺》既是金属材料领域的核心课程,又和工程实践结合非常紧密。该课程一直沿用20世纪的教学大纲,教学内容过于陈旧,又由于该课程“理论性、抽象性、综合性与实践性强”,导致学生难以融会贯通,遇到实际热处理问题无从下... 详细信息

《热处理原理与工艺》既是金属材料领域的核心课程,又和工程实践结合非常紧密。该课程一直沿用20世纪的教学大纲,教学内容过于陈旧,又由于该课程“理论性、抽象性、综合性与实践性强”,导致学生难以融会贯通,遇到实际热处理问题无从下手。基于“新工科”对人才培养的新要求,需对课程内容进行系统的改革。首先,提取该课程的核心知识点——固态相变原理,并深化其教学,提高学生的理论水平。其次,通过精简钢材的传统热处理工艺,使学生更为系统地掌握热处理工艺。最后,通过融入新发展的热处理工艺,以及其他重要金属材料的相变和热处理工艺,进一步帮助学生深刻理解固态相变原理,并培养学生的创新性思维,使其具备解决金属材料热处理相关问题的能力。

关键词：材料科学固态相变新工科改革

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智能手机GNSS数据质量分析与随机模型建立

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大地测量与地球动力学 2024年第7期44卷 661-666页

作者：赵兴旺陶安迪陈健刘超程茂原安徽理工大学空间信息与测绘工程学院安徽省淮南市232001 河海大学地球科学与工程学院南京市211100

为提高移动智能终端定位精度,利用小米8和华为Mate20手机采集多个卫星系统的观测数据并进行质量分析,通过不同卫星系统的伪距残差分别对信噪比模型参数进行估计,最后进行静态伪距单点定位实验。结果表明,手机端观测的BDS和GPS伪距精度接... 详细信息

为提高移动智能终端定位精度,利用小米8和华为Mate20手机采集多个卫星系统的观测数据并进行质量分析,通过不同卫星系统的伪距残差分别对信噪比模型参数进行估计,最后进行静态伪距单点定位实验。结果表明,手机端观测的BDS和GPS伪距精度接近,且高于GLONASS;相较于高度角,伪距残差与信噪比的相关性更强;在信噪比模型参数估计中,小米8拟合效果优于华为Mate20,BDS拟合效果差于其他卫星系统;参数拟合后的信噪比模型在水平和高程方向的定位精度分别为2.37 m和8.38 m,相较于高度角模型,定位精度提升约10%。

关键词：智能手机数据质量分析信噪比模型参数拟合定位精度

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第一性原理研究钛合金中的沉淀强化

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金属学报 2024年第4期60卷 537-547页

作者：程坤陈树明曹烁刘建荣马英杰范群波程兴旺杨锐胡青苗中国科学院金属研究所师昌绪先进材料创新中心沈阳110016 中国科学技术大学材料科学与工程学院沈阳110016 北京理工大学材料学院冲击环境材料技术重点实验室北京100081

为研究合金化对沉淀强化行为的影响,采用第一性原理方法计算了二元Ti-xM(M=Al、V、Cr、Mn、Fe、Co、Ni、Zr、Nb、Mo、Ta、W)合金弹性模量随成分的变化,提出了弹性模量Mo当量概念,以高效计算复杂成分钛合金(如Ti-Al-V合金以及Ti55521)的... 详细信息

为研究合金化对沉淀强化行为的影响,采用第一性原理方法计算了二元Ti-xM(M=Al、V、Cr、Mn、Fe、Co、Ni、Zr、Nb、Mo、Ta、W)合金弹性模量随成分的变化,提出了弹性模量Mo当量概念,以高效计算复杂成分钛合金(如Ti-Al-V合金以及Ti55521)的弹性模量;结合弹性模量及Russell-Brown沉淀强化模型,研究了二元Ti-xM(M=V、Cr、Mn、Fe、Co、Ni、Nb、Mo、Ta、W)合金以及Ti55521合金中的沉淀强化。结果显示,在体积分数及沉淀相颗粒尺寸相同的情况下,Co、Fe、W、Mo、Ni、Mn沉淀强化作用较强,Cr、Nb、Ta强化作用居中,V强化作用最弱。随合金元素含量x增加,沉淀强化作用均有所增强。热机械处理Ti55521合金经短时时效后,沉淀强化作用有所减弱,但长时时效后,沉淀强化效果增强。

关键词：第一性原理钛合金弹性模量沉淀强化强度

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