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Anisotropic Creep Rupture Properties of a Nickel-base Single Crystal Superalloy at High Temperature

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Journal of Materials Science & Technology 2011年第2期27卷 107-112页

作者： Shaohua zhang jian zhang langhong lou Superalloys Division Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The creep rupture properties of a single crystal superalloy were tested at 975℃/255 MPa as a function of the deviation degrees from [001].The misorientation of the specimens away from [001] distributed approximately along a line between [001]-[011] and [001]-[111] boundaries in the triangle of the stereographic *** rupture lifetimes of the specimens were not sensitive to the misorientation until the deviation degree exceeded ～30 *** steps of lattice rotation were found in all specimens during creep,first towards the [001]-[111] boundary,and then to [001] or [111] along the *** slip and strong asymmetric deformation were observed during the first stage of lattice rotation in specimens with large *** rotation mechanism was associated with the activated slip systems according to the calculated Schmid *** impact of lattice rotation on the rupture properties was also discussed.

关键词： Nickel-base single crystal superalloy Stress rupture property Orientation Dislocation

Orientation Dependence of Stress Rupture Properties of a Ni-based Single Crystal Superalloy at 760℃

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Journal of Materials Science & Technology 2012年第3期28卷 229-233页

作者： Shaohua zhang Dong Wang jian zhang langhong lou Superalloys Division Shenyang National Laboratory for Materials ScienceInstitute of Metal ResearchChinese Academyof Sciences72 Wenhua RoadShenyang 110016China

The orientation dependence of creep rupture lives of a single crystal superalloy at 760℃/760 MPa was *** orientations of the specimens tested were about 30°away from [001].The results showed that specimens with orientations on the [001]-[011] boundary had the longest rupture *** deformation of these specimen were controlled by a/2〈110〉 slip and a few stacking faults with two orientations were *** the other hand,specimens with orientations near the [001]-[011] boundary or on the [001]-[111] boundary showed short rupture lives,and stacking faults with single orientation were observed in these *** rupture properties and the deformation mechanisms were discussed based on the dislocation pattern and the calculated Schmid factors for different specimens.

关键词： Single crystal superalloy Stress rupture Orientation

Effect of Withdrawal Rates on Microstructure and Creep Strength of a Single Crystal Superalloy Processed by LMC

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Journal of Materials Science & Technology 2010年第4期26卷 306-310页

作者： Chengbao Liu jian Shen jian zhang langhong lou Superalloys Division Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

A nickel base single crystal （SC） superalloy was directionally solidified using liquid metal cooling （LMC） process at various withdrawal rates. The microstructure was refined as increasing the withdrawal rate from 3 to 12 mm/min. However, higher withdrawal rate of 15 mm/min induced the formation of stray grains. Size and volume fraction of the eutectics were found to decrease with the increasing in withdrawal rate. After solution heat treatment at 1250℃, un-dissolved eutectic was observed in specimens. High temperature creep rupture life was observed to be very sensitive to the fraction of these remaining eutectics. Creep rupture tests at 1000℃/235 MPa showed that refined microstructure and low fraction of the remaining eutectic lead to significant improvement of the rupture life.

关键词： Eutectic Single crystal superalloy Liquid-metal-cooling Withdrawal rate

Evolution of micro-pores in a single crystal nickel-based superalloy during 980℃ creep

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Acta Metallurgica Sinica(English Letters) 2022年第8期35卷 1397-1406页

作者： Yufeng He Shaogang Wang jian Shen Dong Wang Yuzhang Lu langhong lou jian zhang Superalloys Division Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The evolution of micro-pores in a single crystal nickel-based superalloy during creep at 980 ℃/220 MPa was investigated by X-ray computed tomography. Time-dependent ex-situ 3D information including the number, volume fraction, distribution and morphology of micro-pores was analyzed. The results reveal that the signifi cant formation and growth of micro-pores occur at the end of secondary/beginning of tertiary creep stage. The irregular large pores as well as high density pores located at strain concentration region are the major detrimental factors facilitating the creep damage. Creep failure is resulted from the connection of surface cracks induced by oxidation, and the internal cracks generated from growth and merging of micro-pores.

关键词： Single crystal superalloy Creep damage Micro-pore evolution X-ray tomography

Microstructure evolution and crystallography of directionally solidified Al2O3/Y3Al5O12 eutectic ceramics prepared by the modified Bridgman method

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Journal of Materials Science & Technology 2019年第9期35卷 1982-1988页

作者： Xu Wang Nan zhang Yujie Zhong Bailingjiang langhong lou jian zhang Jingyang Wang Shool of Material Science and Engineering Xi'an University of TechnologyXi'an710048China School of Materials Science and Engineering Xi'an Shiyou UniversityXi'an710065China Institute of Metal Research. Chinese Academy of Sciences Shenyang110016China

Large size,high-density(99.97%)and well-organized Al2O3/Y3Al5O12(YAG)eutectic ceramics were prepared by the modified Bridgman *** evolution of the three dimensional microstructure and micropores were *** diameter of the micro-pores and the porosity decreased during directional *** average equivalent diam eter of the micro-pores was 2.41μm in the well-prepared eutectic *** of the pores(98.07%)were smaller than 4μ*** data are comparable to those prepared by the optical floating zone *** as-grown eutectic ceramics were polycrystalline,but the interfaces were well-bonded and there were no amorphous phases in the *** misfits of the different crystallographic relationships were calculated,and the bottleneck of the single-crystal preparation was *** results could provide theoretical guidance for the preparation of large,single-crystal Al2O3/YAG eutectic ceramics by the modified Bridgman method.

关键词： Al2O3/YAG eutectic ceramics Crystallography Interfaces Bridgman method

Microstructural Instability of an Experimental Nickel-Based Single-Crystal Superalloy

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Acta Metallurgica Sinica(English Letters) 2020年第10期33卷 1433-1441页

作者： Bin Yin Guang Xie Xiangwei jiang Shaohua zhang Wei Zheng langhong lou Superalloys Division Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

Microstructural instability with the precipitation of topologically close-packed(TCP)phases of an experimental nickel-based single-crystal superalloy has been investigated.A significant amount of σ phases are distinguished in the interdendritic region of the as-cast samples after thermal exposure at 900℃ for 1000 ***σphases are preferentially precipitated at the periphery of coarse γ/γ′eutectic,and their morphological evolution from needles to granules is *** analysis suggests that the local segregation of Cr and Ti at the periphery of coarse γ/γ′eutectic accounts for the formation ofσphases in the as-cast *** heat treatment with low solution temperature and short holding time,the dendritic segregation of alloying elements(i.e.,W,Re,Ti and Ta)and the volume fraction of γ′phase in the interdendritic region are similar to that of the as-cast ***,no TCP phases are present in the interdendritic region of the heat-treated samples after thermal exposure,which is primarily ascribed to the elimination of local segregation of Cr and Ti near the coarse γ/γ′***,small quantities ofμphases are precipitated in the secondary dendrite arm near the interdendritic region after thermal exposure,due to the increased volume fraction ofγ′phase and the concomitant enrichment of W and Re in theγmatrix.

关键词： Nickel-based single-crystal superalloy Topologically close-packed(TCP)phases Segregation Eutectic

Microstructure and grain orientation evolution of a specially shaped shroud during directional solidification process

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Progress in Natural Science:Materials International 2013年第2期23卷 211-215页

作者： Hongquan Hao Weiguo jiang Guang Xie Gong zhang Yuzhang Lu jian zhang langhong lou Institute of Metal Research Chinese Academy of Sciences

The microstructure and the grain orientations of one shroud prepared by directional solidification process have been investigated using metallographic method and electronic backscatter diffraction (EBSD). The results indicate that the solidification process of the tested shroud is composed of three steps: dendritic branching, the break-up and drift of the dendrite arms and the solidification of the residual liquid. Misoriented grains were formed between the primarily solidified dendrite stems during the process of recalescence which was caused by the accumulation of the solidification latent heat. A low angle grain boundary of 61 was produced across the impinging dendrite fronts.

关键词： Directional solidification Shroud Dendrite Undercooling Low angle grain boundary

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铸造高温合金研发中的应用基础研究

金属学报 2018年第11期54卷 1637-1652页

作者：张健楼琅洪中国科学院金属研究所沈阳110016

铸造高温合金应用于制造航空、航天、能源等领域高端装备的核心热部件,其研发涉及多种材料、多个学科,先进铸造高温合金材料的应用水平(技术成熟度)也是国家工业基础的重要体现。近年来在需求牵引下,我国铸造高温合金材料和精密铸件的... 详细信息

铸造高温合金应用于制造航空、航天、能源等领域高端装备的核心热部件,其研发涉及多种材料、多个学科,先进铸造高温合金材料的应用水平(技术成熟度)也是国家工业基础的重要体现。近年来在需求牵引下,我国铸造高温合金材料和精密铸件的研发取得了显著进展,但也在工程应用中不断暴露问题,技术成熟度偏低,与国际先进水平仍有较大差距。本文结合近年来本课题组承担的材料及铸件研制任务,从先进定向和单晶高温合金材料研制、复杂铸件研制、叶片的服役行为等方面,介绍了相关应用基础研究在高温合金研制任务中发挥的重要作用。

关键词：铸造高温合金叶片基础研究

Plasticity Induced by Twin Lamellar Structure in Magnesium Alloy

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Journal of Materials Science & Technology 2013年第12期29卷 1123-1128页

作者： Xiyan zhang Chao lou jian Tu Qing Liu School of Materials Science and Engineering Chongqing University

Effect of {10-12} twins on the mechanical properties of magnesium alloy has received considerable research interest. A hot-rolled AZ31 Mg alloy sheet was subjected to dynamic plastic deformation with the aim of introducing {10-12} twin lamellar structure. It has been found that higher strength and better ductility are obtained when tensile loading is perpendicular to the c axis of twin region of the twin lamellar structured sample, indicating that the plasticity improvement caused by twins depends on the special strain path. The fracture morphology of the twin lamellar structured sample shows a dimple fracture mode under tensile loading perpendicular to the c axis, while the cleavage fracture with river pattern has been observed in other fractured samples. Above experimental results indicate that the interaction of dislocations and twin lamellae may play an important role in improving mechanical properties of Mg alloy.

关键词： Magnesium alloy Twin lameilar structure Mechanical behavior Plasticity