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High-operating-temperature MWIR photodetector based on a InAs/GaSb superlattice grown by MOCVD

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Journal of Semiconductors 2022年第1期43卷 49-52页

作者： Xiujun Hao Yan Teng He Zhu Jiafeng Liu Hong Zhu Yunlong Huai Meng Li Baile Chen Yong Huang Hui Yang Key Laboratory of Nanodevices and Applications Suzhou Institute of Nano-Tech and Nano-BionicsCASSuzhou 215123China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China School of Information Science and Technology ShanghaiTech UniversityShanghai 201210China

We demonstrate a high-operating-temperature(hot)mid-wavelength InAs/GaSb superlattice heterojunction in-frared photodetector grown by metal-organic chemical vapor deposition.High crystalline quality and the near-zero lattice mis-match of a InAs/GaSb superlattice on an InAs substrate were evidenced by high-resolution X-ray diffraction.At a bias voltage of-0.1 V and an operating temperature of 200 K,the device exhibited a 50%cutoff wavelength of~4.9μm,a dark current dens-ity of 0.012 A/cm^(2),and a peak specific detectivity of 2.3×10^(9) cm·Hz^(1/2)/W.

关键词： hot MWIR InAs/GaSb superlattice aluminum-free MOCVD

hot Corrosion behaviors of Super 304H austenitic stainless steel precoated in Na2SO4-25%NaCI mixture salt film

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Journal of Iron and Steel Research(International) 2018年第11期25卷 1149-1155页

作者： Ping Li Ting-ju Li Jie Zhao Sheng-jiao Pang College of Materials Science and Engineering Dalian University of TechnologyDalian 116024LiaoningChina

hot corrosion rates of Super 304H austenitic stainless steel pre-coated in Na2SO4-25%NaCl mixture salt film in air at 650 ℃ and 750 ℃ have been investigated by corrosion kinetics curves.The corrosion products are examined by means of X-ray diffraction and scanning electron microscopy coupled with energy-dispersive spectrometer,and electron probe micro-analyzer to analyze the scale structure and element distribution of the cross section.The results indicate that the kinetics curves are similar and display parabolic growth,and the mass gain obviously increases with the increasing temperature.A two-layer oxide scale composed of Fe oxides containing CuFe2O4 and Cr2O3 forms on the surface of the alloy and easily exfoliates with extending corrosion time or with improving corrosion temperature.Moreover,a corrosion-affected zone with micropores and micro-cracks appears beneath the oxide scale.It is concluded that the selective oxidation occurs and a protective oxide scale forms at the early corrosion stage.The melt salts destroy the integrity of the oxide scale and accelerate hot corrosion of the alloy by the cyclical oxidation-chlorination during the further corrosion processing.In addition,internal sulfidation also contributes to the corrosion of the alloy.

关键词： Ultra supercriticality hot corrosion Sulfidation Chloridation

hot deformation behaviors of a 9Cr oxide dispersion-strengthened steel and its microstructure characterization

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International Journal of Minerals,Metallurgy and Materials 2019年第5期26卷 597-610页

作者： Yu Shao Li-ming Yu Yong-chang Liu Zong-qing Ma Hui-jun Li Jie-feng Wu State Key Lab of Hydraulic Engineering Simulation and Safety Tianjin Key Lab of Composite and Functional Materials Tianjin University Institute of Plasma Physics Chinese Academy of Sciences

The hot deformation behaviors of a 9 Cr oxide dispersion-strengthened(9 Cr-ODS) steel fabricated by mechanical alloying and hot isostatic pressing(HIP) were investigated. hot compression deformation experiments were conducted on a Gleeble 3500 simulator in a temperature range of 950–1100°C and strain rate range of 0.001–1 s^(-1). The constitutive equation that can accurately describe the relationship between the rheological stress and the strain rate of the 9 Cr-ODS steel was established, and the deformation activation energy was calculated as 780.817 kJ/mol according to the data obtained. The processing maps of 9 Cr-ODS in the strain range of 0.1–0.6 were also developed. The results show that the region with high power dissipation efficiency corresponds to a completely recrystallized structure. The optimal processing conditions were determined as a temperature range of 1000–1050°C with strain rate between 0.003 and 0.01 s^(-1).

关键词： hot deformation constitutive equations processing maps microstructural evolution

hot deformation behavior and workability characteristic of a fine-grained Mg–8Sn–2Zn–2Al alloy with processing map

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Journal of Materials Science & Technology 2019年第6期35卷 1198-1209页

作者： Weili Cheng Yang Bai Shichao Ma Lifei Wang Hongxia Wang Hui Yu Shanxi key Laboratory of Advanced Magnesium-Based Materials Taiyuan University of Technology Taiyuan 030024 China Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of Education Taiyuan University of Technology Taiyuan 030024China School of Materials Science and Engineering Taiyuan University of Technology Taiyuan 030024 China School of Materials Science and Engineering Hebei University of Technology Tianjin 300132 China

The hot deformation behavior of a fine-grained Mg–8 Sn–2 Zn–2 Al(TZA822, in wt%) alloy was investigated in the temperature range of 150–350°C and the strain rate of 0.01–10 s^-1 employing thermomechanical simulator. In most of the cases, the material showed typical dynamic recrystallization(DRX) features i.e., a signal peak value followed by a gradual decrease or to reach a steady state. The work hardening rate was found to increase with decreasing temperature and increasing strain rate, while strain rates had great effects on work hardening behavior. Meanwhile, the constitutive analysis indicated that cross-slip of dislocations was likely to be the dominant deformation mechanism. In addition, the processing map at the strain of 0.1–0.7 showed two stability domains with high power dissipation efficiencies and the optimum hot working parameters for the studied alloy was determined to be 350°C/0.01 s^-1 and 350°C/10 s^-1, at which continuous DRX(CDRX) and discontinuous DRX(DDRX) as main softening mechanism. The instability regions occurred at 200–250°C/10 s^-1 and the main flow instability mechanism was twinning and/or flow localization bands, which were prone to induce cracks and caused in-consistent mechanical properties of the alloy.

关键词： Mg-Sn based alloy hot deformation Processing map Dynamic recrystallization

Crystallization behavior of blast-furnace slag by single hot thermocouple technique

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Journal of Iron and Steel Research(International) 2020年第3期27卷 259-265页

作者： Tie-lei Tian Shuang Cai Yu-zhu Zhang Hong-wei Xing College of Metallurgy and Energy North China University of Science and TechnologyTangshan 063009HebeiChina College of Mechanical Engineering Yanshan UniversityQinhuangdao 066004HebeiChina

The crystallization behavior of blast-furnace slag under isothermal and continuous-cooling conditions was studied using the single hot thermocouple technique.The crystallization phases were obtained using FactSage software and X-ray diffractometry.The crystallization kinetic parameters were calculated by combining these results with the Johnson-Mehl—Avrami model.Under isothermal conditions,the shortest crystallization incubation time was 24 and 18 s when the temperatures were 1300 and 1150℃,and the corresponding critical cooling rates were 4.5 and 14.3℃/s,respectively.At 1270℃,the slag was difficult to crystallize and the fiber-forming rate improved.When the continuous-cooling rate was 6.5℃/s,the slag solidified into a glassy state.The main crystallization phases,gehlenite,akermanite,anorthite,and melangite,were most easily precipitated.The growth factors of melangite and anorthite were approximately 1.63 and 1.68,respectively,which indicated that the crystals nucleated on the surface and grew in two dimensions.

关键词： Blast-furnace slag Cooling rate Crystallization Single hot thermocouple technique

Enhanced tensile properties in a Mg-6Gd-3Y-0.5Zr alloy due to hot isostatic pressing(HIP)

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Journal of Materials Science & Technology 2019年第9期35卷 1860-1868页

作者： B. Zhoua D.Wu R.S.Chen En-hou Han The Group of Magnesium Alloys and Their applications Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

hot isostatic pressing (HIP) was applied to Mg-6Gd-3Y-0.5Zr (GW63) alloy to reduce shrinkage porosity, thus, to enhance the integrity and reliability of castings. During HIP process, shrinkage porosity was closed by grain compatible deformation and subsequent diffusion across the bonding interface. The amount of initial shrinkage porosity was the key factor for shrinkage porosity closure. HIP was testified to be effective on shrinkage porosity reduction in GW63 alloy due to its relatively narrow solidification range and resultant low content of initial shrinkage porosity in most sections, leading to higher tensile properties both in as-cast and cast-T6 condition. The improvement in tensile properties was mainly because of shrinkage porosity reduction and resultant effective rare-earth (RE) elements homogenization and precipitation strengthening.

关键词： hot isostatic pressing Mg-Gd-Y-Zr Shrinkage porosity reduction Tensile properties

Accelerated flow softening and dynamic transformation of Ti-6Al-4V alloy in two-phase region during hot deformation via coarsening αgrain

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Journal of Materials Science & Technology 2020年第1期36卷 160-166页

作者： Xiankun Ji Baoqi Guo Fulin Jiang Hong Yu Dingfa Fu Jie Teng Hui Zhang John J.Jonas College of Materials Science and Engineering Hunan UniversityChangsha 410082China Materials Engineering McGill University3610 University St.Montreal H3A 0C5Canada

The flow softening is an important phenomenon during hot deformation of metallic materials.In the present work,a more evident flow softening of Ti-6 Al-4 V alloy when deformed in two-phase region was observed in coarser a grain sample,which was attributed to an accelerated dynamic transformation from harder α phase into β phases.Notably,full β microstructure was observed in coarse grain samples at strain of 1.2,while retained a phase was observed in fine a grain specimens.In the views of thermodynamics and crystallographic analysis,the in-depth mechanisms of dynamic transformation were further investigated.

关键词： Titanium alloys hot deformation Flow softening Dynamic transformation Grain size

Interfacial microstructure evolution and bonding mechanisms of 14YWT alloys produced by hot compression bonding

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Journal of Materials Science & Technology 2019年第8期35卷 1671-1680页

作者： Liying Zhou Shaobo Feng Mingyue Sun Bin Xu Dianzhong Li Shenyang National Lab. for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China School of Materials Science and Engineering University of Science and Technology of China Shenyang 110016 China

hot compression bonding was first used to join oxide-dispersion-strengthened ferrite steels(14 YWT)under temperatures of 750–1100℃ with a true strain range of 0.11–0.51. Subsequently, the microstructure evolution and mechanical properties of the joints were characterized, revealing that the 14 YWT steels could be successfully bonded at a temperature of at least 950℃ with a true strain of 0.22, without degrading the fine grain and nanoparticle distribution, and the presence of inclusions or micro-voids along the bonding interface. Moreover, the joints had nearly the same tensile properties at room temperature and exhibited a similar fracture morphology with sufficient dimples compared to that of the base material. An electron backscattered diffraction technique and transmission electron microscopy were systematically employed to study the evolution of hot deformed microstructures. The results showed that continuous dynamic recrystallization characterized by progressive subgrain rotation occurred in this alloy, but discontinuous dynamic recrystallization characterized by strain-induced grain boundary bulging and subsequent bridging sub-boundary rotation was the dominant nucleation mechanism. The nuclei will grow with ongoing deformation, which will contribute to the healing of the original bonding interface.

关键词： Oxide dispersion strengthened steels hot compression bonding Dynamic recrystallization Tensile property

Microstructure and mechanical properties of A356 alloy with yttrium addition processed by hot extrusion

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Journal of Rare Earths 2019年第6期37卷 659-667页

作者： Zhifan Wei Yushun Lei Hong Yan Xihao Xu Jiajia He School of Mechanical and Electrical Engineering Nanchang University Key Laboratory of Light Alloy Preparation and Processing in Nanchang City

The effects of the rare earth element yttrium(Y) and hot extrusion on the microstructure and mechanical properties of A356 alloy were investigated by mechanical properties testing and microstructure observation. The results indicate that the addition of Y improves the microstructure of the as-cast alloy. The distribution of primary α-Al is uniform and orderly. The long needle-like eutectic Si phases and β-Fe phases turn to strips and short rods. When the content of Y increases to 0.2 wt%, the mean diameter of aAl(40.3 μm) and the aspect ratio of the eutectic Si phase(2.3) reach the minimum values, which are68.9% and 86.1% lower, respectively, than that of the alloy without Y addition. Under extrusion stress, the shape of the eutectic Si phase is changed from long rod-like to near grain-like after solution treatment.The size of the eutectic Si phase is significantly reduced. The needle-like β-Fe phases are squeezed and broken. The mechanical properties of the as-extruded alloy are significantly improved compared to the as-cast alloy. When the rare earth content is 0.2 wt%, the ultimate tensile strength, hardness and elongation of the alloy reach the maximum values, which are 328.2 MPa, 110.4 HV and 21.3%, respectively, and increase by 42.01%, 37.71% and 481.91%, respectively, in comparison to the as-cast alloy without Y addition.

关键词： A356 alloy with Y addition Micro structure Mechanical properties hot extrusion Rare earths