检索结果-南通市图书馆

Property Characteristics of a TiB_(2P)/Al Composite Fabricated by Squeeze Casting Technology

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2006年第1期22卷 83-86页

作者： Min ZHAO gaohui WU Zuoyong DOU Longtao JIANG School of Materials Science and Engineering Institute of Technology Harbin 150001China

TiB2P/Al composite was successfully fabricated by squeeze casting *** mechanical and tribological properties were evaluated .The elimination of Ti-Al intermetallic compound was confirmed by X-ray diffraction （XRD）*** 45% volume fraction ,the bending strength at ambient temperature was 934 *** the fracture modes included ductile failure of Al matrix and brittle fracture of TiB2 *** dry sliding wear mode ,severe plastic deformation and adhesive wear were found on te worn surfaces of the SiCP/Al composite .But no obvious characteristics of adhesion or abrasion wear were observed on that of the TiB2P/Al composites .At the stedady stage ,the friction coefficient of the SiCP/Al composite was about 0.6 .While that of TiB2P/Al composite was only only about 0.16-0.17.

关键词： TiB2 Aluminum matrix composite Squeeze casting technology Properties

Effects of traverse speed on weld formation,microstructure and mechanical properties of ZK60 Mg alloy joint by bobbin tool friction stir welding

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2021年第12期34卷 238-250页

作者： gaohui LI Li ZHOU Haifeng ZHANG Sanfeng LUO Ning GUO State Key Laboratory of Advanced Welding ami Joining Harbin Institute of TechnologyHarbin 150001China Shandong Provincial Key Laboratory of Special Welding Technology Harbin Institute of Technology(Weihai)Weihai 264209China

ZK60B(Mg-6%Zn-0.6%Zr)alloy joints fabricated by bobbin tool friction stir welding(BTFSW)with various traverse speeds were *** sound joint fabricated by the BTFSW was possible under the appropriate welding *** severe plastic deformation during BTFSW resulted in dispersion and segregation of the Zr-rich particles within the stirred zone(SZ)followed by evolution of a bimodal grain structure with distributed bands of 0.8-1.7μm ultrafine grains and 4.1-7.1μm equiaxed ***-hardness of SZ is substantially reduced in contrast to that of parent metal(PM)in spite of the finer grain size owing to dissolution of Mg-Zn based precipitates having hardening effects on alpha-Mg *** the decrease in traverse speed,randomization degree of the plasticized metal flow increases,which is evidenced by the randomized arc line pattern at the low traverse *** all defect-free joints,the 200 mm/min joint exhibits the weakest isotropy of texture within SZ and the best tensile properties,which has reduced ultimate tensile strength and yield strength by 5.4% and by 22.2%,respectively,as compared to the *** randomized texture hinders the joint fracturing within SZ at low ***,a relatively high elongation of 10.8% was achieved,which corresponded to 72% of the PM value.

关键词： Bobbin tool Friction stir welding(FSW) Magnesium alloys Mechanical properties Microstructure evolution Traverse speed

在线全文

学校读者我要写书评

暂无评论

环塔里木盆地红枣园土壤碳氮磷化学计量特征

中国果树 2024年第3期 60-67,74页

作者：张光鑫王芳霞姚东东王唯赵丰云曹高辉于坤石河子大学农学院特色果蔬栽培生理与种质资源利用兵团重点实验室新疆832003 新疆生产建设兵团第九师林业工作管理站

以环塔里木盆地阿克苏、喀什、和田及巴州4个地区红枣园为研究对象,测定0~20、20~40、40~60 cm土壤有机碳(SOC)、全氮(TN)、全磷(TP)含量并分析其化学计量比。结果表明,果园土壤SOC、TN、TP含量及其化学计量比除TP含量和C∶N外均低于中... 详细信息

以环塔里木盆地阿克苏、喀什、和田及巴州4个地区红枣园为研究对象,测定0~20、20~40、40~60 cm土壤有机碳(SOC)、全氮(TN)、全磷(TP)含量并分析其化学计量比。结果表明,果园土壤SOC、TN、TP含量及其化学计量比除TP含量和C∶N外均低于中国土壤平均水平。0~60 cm土壤SOC、TN含量及C∶P、N∶P均表现为阿克苏地区最高,和田地区最低;土壤TP含量表现为阿克苏地区最高,巴州地区最低;C∶N表现为巴州地区最高,喀什地区最低。随土层深度的增加,4个地区土壤SOC、TN、TP含量及C∶P、N∶P均降低;除和田地区外,其他地区土壤C∶N均随土层深度的增加而升高。冗余分析结果表明,果园土壤SOC、TN、TP含量及其化学计量比受到纬度、经度和电导率等环境因子的影响。综上所述,环塔里木盆地红枣园土壤总体上表现出养分分配不均的现象,建议在施肥过程中适当增加氮肥的施用和有机肥的配施。

关键词：红枣园化学计量比环塔里木盆地

Microstructure and Properties of M40 Carbon Fibre Reinforced Mg-Re-Zr Alloy Composites

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2009年第3期25卷 423-426页

作者： gaohui Wu Meihui Song Ziyang Xiu Ning Wang Wenshu Yang School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

M40 carbon fibre reinforced rare earth magnesium alloy ZM6 composites with fibre volume fraction about 60% were fabricated by pressure infiltration method. The microstructure, interracial morphology, and precipitation were studied by scanning electron microscopy, transmission electron microscopy, and energy dispersive X- ray spectrometer. It was shown that the interfaces between Mg alloy and fibres were well bonded and free from cracks. The Mg12Nd phase was preferentially precipitated at the fibre/matrix interfaces, leading to the segregation of Nd at the interfaces and the dramatic decrease of Mg12Nd precipitation in the matrix far from interfaces. Crystal defects such as high-density dislocations and twins were observed in the matrix near the fibre/matrix interface. A high bending strength （1393 MPa） and elastic modulus （190 GPa） were achieved in M40/ZM6 composite.

关键词： Magnesium matrix composites Microstructure Dislocations Twin

Comparison of seismic effects during deep tunnel excavation with different methods

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2018年第3期17卷 659-675页

作者： Xie Liangtao Yan Peng Lu Wenbo Chen Ming Wang gaohui State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering Ministry of Education Wuhan University

The rapid release of strain energy is an important phenomenon leading to seismic events or rock failures during the excavation of deep *** theoretical analysis of strain energy adjustment during blasting and mechanical excavation,and the interpretation of measured seismicity in the Jin-Ping Ⅱ Hydropower Station in China,this paper describes the characteristics of energy partition and induced seismicity corresponding to different energy release *** theoretical analysis indicates that part of the strain energy will be drastically released accompanied by violent crushing and fragmentation of rock under blast load,and this process will result in seismic events in addition to blasting *** intensity of the seismicity induced by transient strain energy release highly depends on the unloading rate of in-situ *** mechanical excavation,the strain energy,which is mainly dissipated in the deformation of surrounding rock,releases smoothly,and almost no seismic events are produced in this gradual *** test reveals that the seismic energy transformed from the rock strain energy under high stress condition is roughly equal to that coming from explosive energy,and the two kinds of vibrations superimpose together to form the total blasting excavation-induced *** addition,the most intense seismicity is induced by the cut blasting delay; this delay contributes 50% of the total seismic energy released in a blast *** mechanical excavation,the seismic energy of induced vibration（mainly the low intensity acoustic emission events or mechanical loading impacts）,which accounts only for 1.5‰ of that caused by in-situ stress transient releasing,can be ignored in assessing the dynamic response of surrounding rock.

关键词： seismicity energy release rate blasting excavation mechanical excavation seismic energy

Bryophyte-like Fossil （Parafunaria sinensis） from Early-Middle Cambrian Kaili Formation in Guizhou Province, China

在线全文

学校读者我要写书评

暂无评论

Acta Botanica Sinica 2004年第2期46卷 180-185页

作者： YANGRui-Dong MAOJia-Rer ZHANGWei-Hua JIANGLi-Jun gaohui GuizhouUniversityofTechnology Guiyang550003China

Abundant well-preserved animal and macroalgal fossils were discovered in the Early-MiddleCambrian Kaili Formation of Taijiang County, Guizhou Province, China, which constitute the Kaili Biota,named as one of the three important Burgess Shale-type faunas. The bryophyte-like fossil (Parafunariasinensis Yang gen. et sp. nov) was discovered in the horizon of occurrence of Macroalgal fossils. The fossilof P. sinensis possesses typical characters of bryophyte, such as whorled leaves, capsule and seta, andcomplex rhizoid or foot. We infer that the bryophyte-like fossil could be the ancestor of bryophyte. Thediscovery provides a new lead for further study on the origin and evolution of bryophyte or land plant.

关键词：类似藓类植物凯里组中寒武世贵州化石生物群

Mechanical Properties of C_f/Mg Composites Fabricated by Pressure Infiltration Method

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2010年第10期26卷 931-935页

作者： Meihui Songt gaohui Wu Wenshu Yang Wei Jia Ziyang Xiu Guoqin Chen School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

The carbon fibers and the woven reinforced magnesium matrix composites were fabricated by pressure infiltration method. Effects of fiber species, fiber arrangement, hybrid particles and environment temperature on microstructures and properties of the composite were studied. Results showed that the mechanical properties at ambient temperature were affected by interfacial reaction. The magnesium matrix composites reinforced with graphite fibers showed higher strength and elastic modulus due to less interfacial reaction. during loading, the fibers were pulled out and the load was transferred through the interfaces, then the fiber bundles were fractured, finally the whole specimen failed. The introduction of hybrid SiC particles during fabrication can improve the mechanical properties of the magnesium matrix composites. Moreover, taking orthogonal carbon fiber woven as reinforcement can modify the anisotropy and reliability of materials.

关键词： Magnesium matrix composites Mechanical property Interfacial reaction Pressure infiltration

Synthesis of C_f/TiAl_3 Composite by Infiltration-In Situ Reaction

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2009年第6期25卷 803-806页

作者： Yanmei Liu Ziyang Xiu Yongliang Guo Longtao Jiang Wensu Yang gaohui Wu School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China Research Academy of Science and Industry Technology Harbin Institute of Technology Harbin 150001 China Analysis and Measurement Center Harbin Institute of Technology Harbin 150001 China

Infiltration-in situ reaction synthesis of Cf/TiAl3 composite was investigated. The as-cast material was obtained by titanium particles, carbon fibers and pure aluminum. Titanium particles and carbon fibers were mixed and pressed to form a preform firstly, and then molten pure aluminum was pressed into the preform, subsequently, cooled rapidly. In situ reaction samples were obtained by heating the as-cast material from 600 to 1000℃ for I h. The microstructural evolution of in situ reaction samples was analyzed by scanning electron microscopy and energy dispersive X-ray. In addition, the phase composition of products was inspected by X-ray diffraction. Experimental results showed that the dominant product of TiAl3 and a small amount of Al4C3 were formed at low temperature. While TiAl3 was not stable at high temperature, along with its decrease, TiC phase became favorable. In the final products, TiAl3, TiC and Al4C3 were detected. Thus, the in situ reaction for Ti-Al-C system composite proceeded a formed-decomposed-precipitated mechanism.

关键词： Composites Ti-Al Intermetallics In situ reaction Microstructure

Microstructure and Mechanical Properties of 45 vol.%SiC_p/7075Al Composite

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2015年第9期31卷 930-934页

作者： Ziyang Xiu Wenshu Yang Ronghua Dong Murid Hussain Longtao Jiang YongXing Liu gaohui Wu State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Department of Material Science and Engineering Harbin Institute of Technology Department of Chemical Engineering COMSATS Institute of Information Technology

Microstructure and mechanical behavior of high volume content SiCp/7xxxAl composites have not been explored yet. Therefore, in the present work, 45 vol.% SiCp/7075Al composite has been prepared by pres- sure infiltration method. High density dislocations were found around SiC/Al interface in SiCp/7075Al composite after water-quenching and aging treatment. Fine dispersed nano-η＇ phases were observed after the aging treatment. Adverse to other SiCp/Al composites prepared by the pressure infiltration method, an interface layer was observed between SiC particles and AI matrix. Furthermore, high-resolution trans- mission electron microscopy （HRTEM） observation indicated that this interface layer was coherent/semi- coherent with that of the SiC particles. 45 vol.% SiCp/7075Al composite demonstrated high tensile strength （630 MPa） and micro-ductility. Compared to aged SiCp/2024Al composite, the aged SiCp/7075Al com- posite showed an increase of about 200% in the tensile strain and 90% in the tensile strength, respectively. It is speculated that nano-η＇ phases in the Al matrix significantly contributed to the strengthening effect while the interface layer between SiC and AI matrix might be beneficial to the strength and plasticity of SiCp/7075Al composite.

关键词： Metal matrix composite7075Al InterfaceNano precipitationMechanical properties