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烧结温度对(Ti_(5)Si_(3)+TiC+TiB)/Ti复合材料组织和力学性能的影响

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材料科学与工艺 2024年第2期32卷 89-96页

作者：崔凯强姜中涛敬小龙韩威成都大学机械工程学院成都610106 重庆文理学院材料科学与工程学院材料表界面科学重庆市重点实验室重庆402160

为了获得性能优异的钛基复合材料和解决单一增强相对性能提升有限等问题,以Ti粉、SiC粉、TiB_(2)粉、C粉为原料,采用粉末冶金法,在不同烧结温度下原位自生制备了(Ti_(5)Si_(3)+TiC+TiB)/Ti复合材料。通过XRD、SEM、万能试验机等设备表... 详细信息

为了获得性能优异的钛基复合材料和解决单一增强相对性能提升有限等问题,以Ti粉、SiC粉、TiB_(2)粉、C粉为原料,采用粉末冶金法,在不同烧结温度下原位自生制备了(Ti_(5)Si_(3)+TiC+TiB)/Ti复合材料。通过XRD、SEM、万能试验机等设备表征了复合材料的微观组织和力学性能。结果表明:随烧结温度的升高,复合材料的致密度提高,平均晶粒尺寸逐渐增大;烧结温度的升高使增强相数量增加的同时减少了较低烧结温度下的团聚现象。复合材料的洛氏硬度、屈服强度、抗拉强度随烧结温度的升高先增大后减小,断裂应变下降不显著。在1300℃下,(Ti_(5)Si_(3)+TiC+TiB)/Ti具有最佳的综合力学性能,烧结态试样的抗压强度达到最高2435 MPa,屈服强度1649 MPa,洛氏硬度49.1HRC,断裂应变28.7%。分析可知,微米尺寸的TiC、TiB和亚微米尺寸的Ti_(5)Si_(3)增强相的协同作用在显著提高复合材料强度的同时也保持了一定的塑性。(Ti_(5)Si_(3)+TiC+TiB)/Ti复合材料的增强方式以细晶强化、弥散强化和载荷传递强化为主。

关键词：钛基复合材料 Ti_(5)Si_(3)&TiC&TiB 烧结温度显微组织力学性能

Unveiling annealing texture formation and static recrystallization kinetics of hot-rolled Mg-Al-Zn-Mn-Ca alloy

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Journal of Materials Science & Technology 2020年第8期36卷 104-118页

作者： Qinghang Wang Bin jiang Aitao Tang Jie Fu zhongtao jiang Haoran Sheng Dingfei Zhang Guangsheng Huang Fusheng Pan State Key Laboratory of Mechanical Transmissions College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Chongqing Academy of Science and Technology Chongqing 401123China Research Institute for New Materials Technology Chongqing University of Arts and SciencesChongqing 402160China Shanghai Aerospace Equipment Manufactory Shanghai 200245China

The development of Mg-Al-Zn-Mn-Ca series alloys provides a potential prospect to achieve high strength and formability at room temperature(RT).The formation of elliptical annular texture is treated as a crucial factor for the enhanced RT formability.However,the origin of such an elliptical annular texture formation has been rarely reported.Herein,we unveiled the formation and evolution of elliptical annular texture in the hot-rolled Mg-1.6 Al-0.8 Zn-0.4 Mn-0.5 Ca(AZMX1100,wt.%)alloy after annealing at different temperatures for 1 h,and its static recrystallization(SRX)kinetics in given annealing temperature for different time.The results revealed that the formation of elliptical annular texture in the hot-rolled AZMX1100 alloy after annealing was derived from nucleation-oriented SRX mechanism,which took place in 200-300°C,induced by cracked chain-shaped Al2 Ca phases,contraction twins,intersections of double twins,intersections of double twins and grain boundaries and non-basal slips.On further annealing from300-450°C,the grains with 45°–70°transverse direction(TD)preferentially grew,which made elliptical annular texture extended along the TD.Based on the Johnson-Mehl-Avrami-Kolmogorov(JMAK)model,Avrami exponent n value was estimated to be 0.68–1.02,attributed to non-random SRX nucleation,giving rise to the lower activation energy QRof nucleation of^74.24 k J/mol.Since the co-segregation of Al,Zn and Ca atoms in grain boundaries created a strong interaction of solutes and grain boundaries,the hot-rolled AZMX1100 alloy exhibited the higher activation energy Qg(~115.48 k J/mol)of grain growth.

关键词： Mg-Al-Zn-Mn-Ca alloy Elliptical annular texture Nucleation Grain growth Static recrystallization kinetics

Diffusion behavior and reactions between Al and Ca in Mg alloys by diffusion couples

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Journal of Materials Science & Technology 2018年第2期34卷 291-298页

作者： Jiahong Dai Hong Xiao Bin jiang Hongmei Xie Cheng Peng zhongtao jiang Qin Zou Qingshan Yang Fusheng Pan College of Mechanical and Electrical Engineering Yangtze Normal University Chongqing 408100 China State Key Laboratory of Mechanical Transmissions College of Materials Science and Engineering Chongqing University Chongqing 400044. China Chongqing Academy of Science and Technology Chongqing 401123. China Research Institute for New Materials Technology Chongqing University of Arts and Sciences Chongqing 402160 China School of Metallurgy and Materials Engineering Chongqing University of Science and Technology Chongqing 401331 China

The diffusion behavior and reactions between AI and Ca in Mg alloys by diffusion couple method were investigated. Results demonstrate that Al2Ca is the only phase existing in the diffusion reaction layers. The volume fraction of Al2Ca in diffusion reaction layers increases linearly with temperature. The standard enthalpy of formation for intermetallic compounds was rationalized on the basis of the Miedema model. Al-Ca intermetallic compounds were preferable to form in the Mg-Al-Ca ternary system under the same conditions. Over the range of 350-400℃, the structure of Al2Ca is more stable than that of Al4Ca, Al14Ca13and Al3Ca8, The growth constants of the layer I, layer II and entire diffusion reaction layers were determined. The activation energies for the growth of the layer I, layer II and entire diffusion reaction layers were （80.74 ± 3.01 ） kJ/mol, （93.45 ±2.12） kJ/mol and （83.52 ±1.50） kJ/mot, respectively. In layer I and II, AI has higher integrated interdiffusion coefficients D^i^Int,layer layer than Ca. The average effective interdiffusion coefficients D^Al^eff values are higher than D^Ca^eff in the layer I and II.

关键词： Magnesium alloys Diffusion behavior Interface lntermetallic compounds

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脉冲激励下介质阻挡放电负载的特性研究

高压电器 2024年第5期60卷 171-178,188页

作者：方文睿唐雄民江天鸿李仲涛广东工业大学自动化学院广州510006

脉冲激励能大幅度提升介质阻挡放电(dielectric barrier discharge,DBD)负载的放电效率。针对传统的实验研究由于受到实验环境和材料等的限制,无法对脉冲激励下介质阻挡放电的放电特性进行更细致的研究的现状。文中以电压型脉冲激励下... 详细信息

脉冲激励能大幅度提升介质阻挡放电(dielectric barrier discharge,DBD)负载的放电效率。针对传统的实验研究由于受到实验环境和材料等的限制,无法对脉冲激励下介质阻挡放电的放电特性进行更细致的研究的现状。文中以电压型脉冲激励下填充气体为氩气(Ar)的DBD型负载为研究对象,通过构建DBD负载的一维流体模型对该模型的放电曲线以及在不同脉冲参数和介质层参数的条件下DBD的放电特性进行研究。结果表明:DBD负载在一个周期内产生两次极性相反的放电,第一次放电强度比第二次放电强度要高。此外,通过对放电过程的电气量的时空特征研究得出,可以通过提高脉冲电压的幅值、缩短脉冲升降沿时间、选择相对介电常数高的材料以及减少介质层厚度的方法来提高DBD负载的性能。

关键词：介质阻挡放电脉冲电压数值模拟特性分析

Influence of minor Ce additions on the microstructure and mechanical properties of Mg-1.0Sn-0.6Ca alloy

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Journal of Materials Science & Technology 2020年第2期37卷 26-37页

作者： Yanfu Chai Chao He Bin jiang Jie Fu zhongtao jiang Qingshan Yang Haoran Sheng Guangsheng Huang Dingfei Zhang Fusheng Pan State Key Laboratory of Mechanical Transmissions College of Materials Science and EngineeringChongqing UniversityChongqing400044China Chongqing Academy of Science and Technology Chongqing401123China Research Institute for New Materials Technology Chongqing University of Arts and SciencesChongqing402160China School of Metallurgy and Material Engineering Chongqing University of Science and TechnologyChongqing401331China Shanghai Aerospace Equipment Manufactory Shanghai200245China

The microstructure and mechanical properties of Mg-Sn-Ca-Ce alloys with different Ce contents(0.0,0.2,0.5,1.0 wt%)were studied at room temperature.Ce additions to ternary Mg-Sn-Ca alloy resulted in grain refinement as well as a change in the category of second phase from CaMgSn to(Ca,Ce)Mg Sn and Mg12Ce.The volume fraction of second phase increased with rising Ce content,which aggravated the restriction of DRXed grain growth during the extrusion process and eventually led to texture weakening of as-extruded Mg-Sn-Ca based alloys.In terms of plasticity,owing to vigorously activated basal slip and homogeneous distributed tensile strain in tension,the tensile ductility of as-extruded alloys reached the maximum value of 27.6%after adding 0.2 wt%Ce,which enhanced by about 26%than that of ternary MgSn-Ca alloy.However,further Ce additions(0.5 and 1.0 wt%)would coarsen the second phase particles and then impair ductility.The tension-compression yield asymmetry of as-extruded Mg-Sn-Ca ternary alloy was alleviated greatly via Ce additions,due to the joint effects of grain refinement,increased amount of strip distributed second phase particles and texture weakening.

关键词： Mg-Sn-Ca alloy Ce content Microstructure Texture Mechanical properties

Comparison of microstructures and mechanical properties of composite extruded AZ31 sheets

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Journal of Magnesium and Alloys 2019年第4期7卷 547-554页

作者： Yanfu Chai Yan Song Bin jiang Jie Fu zhongtao jiang Qingshan Yang Haoran Sheng Guangsheng Huang Dingfei Zhang Fusheng Pan State Key Laboratory of Mechanical Transmissions College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Chongqing Academy of Science and Technology Chongqing 401123China Research Institute for New Materials Technology Chongqing University of Arts and SciencesChongqing 402160China Shanghai Aerospace Equipment Manufactory Shanghai 200245China

The microstructures and mechanical properties of the composite extruded AZ31/AZ31 and AZ31/4047 Al sheets were investigated and made a comparison to the conventional extruded AZ31 sheet.Owing to the introduced intense shear deformation at the interface during the composite extrusion,grain refinement and tilted texture were detected in AZ31 layers of the AZ31/AZ31 and AZ31/4047 Al sheets,while the conventional extruded AZ31 sheet exhibited a relative coarse,inhomogeneous microstructure and strong basal texture.The compressiontension yield ratio was increased gradually from the AZ31 to the AZ31/AZ31 and AZ31/4047 Al sheets.Besides,the AZ31/4047 Al sheet could successfully accomplish the whole bending forming process at room temperature,while the AZ31 and AZ31/AZ31 sheets were both bend-formed to failure with significant cracks in the outer tensile region under the identical bending parameters.Moreover,under the same bending strain,both the outward offset degree of strain neutral layer and the sheet thickening were more serious in the AZ31/4047 Al composite sheet than those of the AZ31 and AZ31/AZ31 sheets.The foremost reason was the quite wide gap of material properties between Mg alloy AZ31 layer(tensile loading in the outer region)and Al 4047 layer(compressive loading in the inner region).

关键词： Mg alloy sheet Composite extrusion Tension-compression yield asymmetry Bendability

免疫检查点抑制剂在治疗微卫星高度不稳定/错配修复缺陷型结直肠癌中的研究进展

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实用药物与临床 2024年第6期27卷 469-476页

作者：姜忠韬李阳菅凌燕中国医科大学附属盛京医院药学部辽宁沈阳110004

在患有微卫星高度不稳定性(MSI-H)或错配修复缺陷(dMMR)型结直肠癌(CRC)患者中,免疫检查点抑制剂(ICIs)具有良好的疗效。本文对MSI-H/dMMR型结直肠癌的流行病学与生物学特点、ICIs对其治疗的临床效果及ICIs毒性与不良反应进行综述。

关键词：结直肠癌错配修复缺陷微卫星高度不稳定性免疫检查点抑制剂

Influence of different extrusion processes on mechanical properties of magnesium alloy

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Journal of Magnesium and Alloys 2014年第3期2卷 220-224页

作者： Qingshan Yang Bin jiang Hucheng Pan Bo Song zhongtao jiang Jiahong Dai Lifei Wang Fusheng Pan Chongqing Academy of Science and Technology Chongqing 401123China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) Northeastern UniversityShenyang 110004Liaoning ProvinceChina Faculty of Materials and Energy Southwest UniversityChongqing 400715China

AZ31 Mg alloy sheets were processed by the conventional symmetrical extrusion(CSE)and the asymmetric extrusion(ASE).Progressive-asymmetric extrusion(PASE)and severe strain-asymmetric extrusion(SASE)were employed for ASE processes.The texture at near-surface and mid-layer zones of ASE sheets was diverse penetrating the normal direction(ND).This was attributed to an additional asymmetric shear strain deformation during the ASE process.(0002)basal planes of PASE sheets tilt to the shear deformation direction.Meanwhile,the basal texture intensity of PASE sheets has been weakened compared with one in CSE sheets.Grain refinement and tilted weak basal texture obtained by SASE process dramatically enhances the room temperature strength and plasticity of the extruded AZ31 magnesium alloy sheets.The microstructure and mechanical responses were examined and discussed.

关键词： Mg alloys Texture Microstructure Extrusion Shear

Machine-learning-empowered multispectral metafilm with reduced radar cross section,low infrared emissivity,and visible transparency

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Photonics Research 2022年第5期10卷 1146-1156页

作者： RUICHAO ZHU JIAFU WANG JINMING jiang CUILIAN XU CHE LIU YUXIANG JIA SAI SUI zhongtao ZHANG TONGHAO LIU ZUNTIAN CHU JUN WANG TIE JUN CUI SHAOBO QU Shaanxi Key Laboratory of Artificially-Structured Functional Materials and Devices Air Force Engineering UniversityXi’an 710051China Institute of Electromagnetic Space Southeast UniversityNanjing 210096China State Key Laboratory of Millimeter Wave Southeast UniversityNanjing 210096China

For camouflage applications,the performance requirements for metamaterials in different electromagnetic spectra are usually contradictory,which makes it difficult to develop satisfactory design schemes with multispectral compatibility.Fortunately,empowered by machine learning,metamaterial design is no longer limited to directly solving Maxwell’s equations.The design schemes and experiences of metamaterials can be analyzed,summarized,and learned by computers,which will significantly improve the design efficiency for the sake of practical engineer-ing applications.Here,we resort to the machine learning to solve the multispectral compatibility problem of metamaterials and demonstrate the design of a new metafilm with multiple mechanisms that can realize small microwave scattering,low infrared emissivity,and visible transparency simultaneously using a multilayer back-propagation neural network.The rapid evolution of structural design is realized by establishing a mapping between spectral curves and structural parameters.By training the network with different materials,the designed network is more adaptable.Through simulations and experimental verifications,the designed architecture has good accuracy and robustness.This paper provides a facile method for fast designs of multispectral metafilms that can find wide applications in satellite solar panels,aircraft windows,and others.

关键词： transparency visible film