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Phase Evolution and Thermal Expansion Behavior of aγ′Precipitated Ni-Based Superalloy by Synchrotron x-ray diffraction

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Acta Metallurgica Sinica(English Letters) 2022年第1期35卷 93-102页

作者： Zhiran Yan Qing Tan Hua Huang Hailong Qin Yi Rong Zhongnan Bi Runguang Li Yang Ren Yandong Wang State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing100083China Department of Microstructure Physics and Alloy Design Max-Planck-Institut Für Eisenforschung GmbH40237DüsseldorfGermany Department of Materials Imperial College LondonKensingtonLondonSW72AZUK Beijing Key Laboratory of Advanced High Temperature Materials Central Iron and Steel Research InstituteBeijing100081China Department of Mechanical Engineering Technical University of Denmark2800Kongens LyngbyDenmark x-ray Science Division Advanced Photon SourceArgonne National LaboratoryArgonneIL60439USA

The phase evolution and thermal expansion behavior in superalloy during heating play an essential role in controlling the size and distribution of precipitates,as well as optimizing thermomechanical *** x-ray diffraction is able to go through the interior of sample and can be carried out with in situ environment,and thus,it can obtain more statistics information in real time comparing with traditional methods,such as electron and optical *** this study,in situ heating synchrotron x-ray diffraction was carried out to study the phase evolution in a typicalγ′phase precipitation strengthened Ni-based superalloy,Waspaloy,from 29 to 1050°***γ′,γ,M_(23)C_(6)and M C phases,including their lattice parameters,misfits,dissolution behavior and thermal expansion coefficients,were mainly ***γ′phase and M_(23)C_(6)carbides appeared obvious dissolution during heating and re-precipitated when the temperature dropped to room *** with the microscopy results,we can indicate that the dissolution of M_(23)C_(6)leads to the growth of grain andγ′phase cannot be completely dissolved for the short holding time above the solution ***,the coefficients of thermal expansions of all the phases are calculated and fitted as polynomials.

关键词： Superalloy Waspaloy Lattice misfit Coefficients of thermal expansion x-ray diffraction Synchrotron radiation

x-ray diffraction investigation of amorphous calcium phosphate and hydroxyapatite under ultra-high hydrostatic pressure

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International Journal of Minerals,Metallurgy and Materials 2015年第11期22卷 1225-1231页

作者： Elisa Lam Qinfen Gu Peter J.Swedlund Sylvie Marchesseau Yacine Hemar School of Chemical Sciences The University of Auckland Australian Synchrotron Université Montpellier 2 UMR IATE Pl.E Bataillon34095 Montpellier cedex 5 France

The changes in the crystal structures of synthetically prepared amorphous calcium phosphate（ACP） and hydroxyapatite（HAP） in water（1：1 mass ratio） were studied by synchrotron x-ray diffraction（xRD） under ultra-high hydrostatic pressures as high as 2.34 GPa for ACP and 4 GPa for HAP. At ambient pressure, the xRD patterns of the ACP and HAP samples in capillary tubes and their environmental scanning electron micrographs indicated amorphous and crystalline characteristics for ACP and HAP, respectively. At pressures greater than 0.25 GPa, an additional broad peak was observed in the xRD pattern of the ACP phase, indicating a partial phase transition from an amorphous phase to a new high-pressure amorphous phase. The peak areas and positions of the ACP phase, as obtained through fitting of the experimental data, indicated that the ACP exhibited increased pseudo-crystalline behavior at pressures greater than 0.96 GPa. Conversely, no structural changes were observed for the HAP phase up to the highest applied pressure of 4 GPa. For HAP, a unit-cell reduction during compression was evidenced by a reduction in both refined lattice parameters a and c. Both ACP and HAP reverted to their original structures when the pressure was fully released to ambient pressure.

关键词： calcium phosphate hydroxyapatite high hydrostatic pressure x-ray diffraction

x-ray diffraction of Dust Particles in Spring Beijing

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Acta Geologica Sinica(English Edition) 2011年第1期85卷 254-262页

作者： ZHENG Nan WANG Hejin xU Tingjing LI Ting Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education China School of Earth and Space Sciences Peking University Beifing 100871 State Key Laboratory for Environmental Simulation and Pollution Control College of Environmental Science and Engineering Peking University Beijing 100871

x-ray diffractometry was utilized to study the mineralogical characteristics of the inhalable particles （PM10） sampled during two dust storms in Beijing city on March 18th and May 21st, 2008. We confirm, for the first time, that there stably exists ammonium chloride in the atmosphere when temperature is low. The total sulfates particles were affected by relative humidity. Both species and concentration of sulfates decreased first and then grew back by the end of each dust storm. Koninckite, a phosphate mineral never reported as particulate aerosol before, was identified. Meanwhile, our result shows that a chemical modification on dust minerals occurs during long range transportation. PM10 samples collected during the period of dust storms were dominated by crustal minerals such as quartz, illite/smectite, illite, chlorite, feldspar and calcite, and were notably higher in concentration than that in normal periods of time. The amounts of total sulfates, calcite and feldspar altered in each dust storm. It is derived from 24-hour isentropic backward trajectories that two dust events in spring 2008 originated in different sources.

关键词： dust storm PM10 x-ray diffraction ammonium chloride

x-ray diffraction and Raman Spectroscopy Characterization of Isotropic Pyrocarbon Obtained by Hot Wall Chemical Vapor Deposition

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Journal of Wuhan University of Technology(Materials Science) 2013年第2期28卷 358-361页

作者：张东生 LI kezhi JIA Yan GUO Lingjun LI Hejun LU Jinhua State Key Laboratory of Solidification Processing Northwestern Polytechnical University

Varying the flow rate of natural gas from 50 to 80 to 120 l/h, isotropic pyrocarbon produced by hot wall chemical vapor deposition at 1000 ℃ were examined by x-ray diffraction and Raman spectroscopy. The x-ray data were evaluated by Scherrer equation, and the intensity ratio of D to G band derived from Raman data was used to evaluate the lateral extension of isotropic pyrocarbon. The experimental results show that the d002-spacing of isotropic pyroearbon decreases from 0.3499 nm to 0.3451 nm, while the stack height increases from 6.5 to 8.4 nm with the increase of flow rate of natural gas. The intensity ratio of D to G band and lateral extension of isotropie pyrocarbon increases with natural gas flow rate increasing. After heat treatment, all the crystallite parameters （stack height, lateral extension, and d002-spacing） decrease, indicating the improvement of the arrangement of the basic structural units of isotropic pyrocarbon.

关键词： isotropic pyrocarbon x-ray diffraction raman spectroscopy chemical vapor deposition characterization

Influence of Cryorolling on the Precipitation of Cu–Ni–Si Alloys: An In Situ x-ray diffraction Study

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Acta Metallurgica Sinica(English Letters) 2018年第10期31卷 1089-1097页

作者： Wei Wang Zong-Ning Chen En-Yu Guo Hui-Jun Kang Yi Liu Cun-Lei Zou Ren-Geng Li Guo-Mao Yin Tong-Min Wang Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province) School of Materials Science and Engineering Dalian University of Technology Shanghai Synchrotron Radiation Facility Shanghai Institute of Applied Physics Chinese Academy of Sciences

The effect of cryorolling on the precipitation process of deformed Cu-Ni-Si alloys was investigated through in situ synchrotron x-ray diffraction technique. The results demonstrate that the precipitation process is significantly accelerated by cryorolling. Cryorolling produces higher dislocation density, which provides more heterogeneous nucleation sites for Ni2Si precipitates, hence promotes precipitation. In the early stage of aging, the enhanced nucleation of precipitates accelerates the depletion of supersaturation, and finer precipitates are obtained. In addition, recrystallization is promoted as a result of high stored energy in the cryorolled Cu-Ni-Si alloys, which facilitates the formation of discontinuous precipitation in the late stage of aging.

关键词： Copper alloy Cryogenic Rolling Aging precipitation Synchrotron radiation x-ray diffraction

High-pressure effect on inverse spinel LiCuVO_4:x-ray diffraction and Raman scattering

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Chinese Physics B 2013年第1期22卷 415-420页

作者：梁桁楠马春丽杜菲崔啟良邹广田 State Key Laboratory of Superhard Materials College of Physics Jilin University

The effect of external quasi-hydrostatic pressure on the inverse spinel structure of LiCuVO4 was studied in this paper. High-pressure synchrotron x-ray diffraction and Raman spectroscopy measurements were carried out at room temperature up to 35.7 and 40.3 GPa, respectively. At a pressure of about 20 GPa, both Raman spectra and x-ray diffraction results indicate that LiCuVO4 was transformed into a monoclinic phase, which remained stable up to at least 35.7 GPa. Upon release of pressure, the high-pressure phase returned to the initial phase. The pressure dependence of the volume of low pressure orthorhombic phase and high-pressure monoclinic phase were described by a second-order Birch-Murnaghan equation of state, which yielded bulk modulus values of B0 = 197 （5） and 232（8） GPa, respectively. The results support the empirical suggestion that the oxide spinels have similar bulk modulus around 200 GPa.

关键词： high pressure inverse spinel LiCuVO4 x-ray diffraction Raman scattering

In-situ high pressure x-ray diffraction studies of orthoferrite SmFeO_3

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Chinese Physics B 2014年第6期23卷 635-638页

作者：李娜娜李岩李会唐瑞莲赵永胜韩丹丹马艳梅崔启良朱品文王欣 State Key Laboratory of Superhard Materials Jilin University

The high-pressure behaviors of SmFeO3 are investigated by angle-dispersive synchrotron x-ray powder diffraction under a pressure of up to 40.3 GPa at room temperature. The crystal structure of SmFeO3 remains stable at up to the highest pressure. The different pressure coefficients of the normalized axial compressibility are obtained to be βa = 0.60 × 10-3 GPa-1,βb = 0.79 × 10-3 GPa-1, βc = 1.28 × 10-3 GPa- 1, and the bulk modulus （B0） is determined to be 293（3） GPa by fitting the pressure-volume data using the Birch-Murnaghan equation of state. Furthermore, the larger compressibility of the FeO6 octahedra suggests the evolution of the orthorhombic structure towards higher symmetry configuration at high pressures.

关键词： crystal structure high-pressure x-ray diffraction

Liquid structure of pure iron by x-ray diffraction

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Journal of University of Science and Technology Beijing 2004年第2期11卷 161-164页

作者： JunLuo QijieZhai PeiZhao xuboQin MaterialsScienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China SchoolofMaterialsScienceandEngineering ShanghaiUniversityShanghai200072China CentralIron＆SteelResearchInstitute Beijing100081China TheKeyLaboratoryofStateEducationMinistryforLiquidStructureandHeredityofMaterials ShandongUniversityJinan250061China

The liquid structure of pure iron at 1540, 1560 and 1580 deg C was studied byx-ray diffraction. The results show that near the melting point there is a medium-range orderstructure that fades away with the increasing temperature. The average nearest distance of atoms isalmost independent of the melts temperature, but the average coordination number, the atom clustersize and the atom number in an atom cluster all decrease with the increasing temperature of themelt. Near the melting point there are a lot of atom clusters in the pure iron melt. The atomcluster of pure iron has the body-centered cubic lattices, which are kept from the solid state. Andthe body-centered cubic lattices connect into network by occupying a same edge. The atoms in thesurrounding of the atom clusters are arranged disorderly.

关键词： pure iron liquid structure x-ray diffraction

Investigation of Ge-Si Atomic Interdiffusion in Ge Nano-dots Multilayer Structure by Double Crystal x-ray diffraction

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Journal of Materials Science & Technology 2007年第3期23卷 301-303页

作者： Wenhua SHI Lei ZHAO Liping LUO Qiming WANG State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China

The fluctuations of the strained layer in a superlattice or quantum well can broaden the width of satellite peaks in double crystal x-ray diffraction （DCxRD） pattern. It is found that the width of the 0^th peak is directly proportional to the fluctuation of the strained layer if the other related facts are ignored. By this method, the Ge-Si atomic interdiffusion in Ge nano-dots and wetting layers has been investigated by DCxRD. It is found that thermal annealing can activate Ge-Si atomic interdiffusion and the interdiffusion in the nano-dots area is much stronger than that in the wetting layer area. Therefore the fluctuation of the Ge layer decreases and the distribution of Ge atoms becomes homogeneous in the horizontal Ge （GeSi actually） layer, which make the width of the 0^th peak narrow after annealing.

关键词： x-ray diffraction GeSi Nano-dots Annealing Island