检索结果-南通市图书馆

New insights into microstructural changes during transient liquid phase bonding of GTD-111 superalloy

Transactions of Nonferrous Metals Society of China 2021年第9期31卷 2703-2715页

作者： Javad ASADI seyed abdolkarim sajjadi Hamid OMIDVAR Materials and Metallurgical Engineering Department Faculty of EngineeringFerdowsi University of MashhadMashhadIran Department of Materials and Metallurgical Engineering Amirkabir University of Technology(Tehran Polytechnic)TehranIran

The effects of joining temperature(TJ)and time(tJ)on microstructure of the transient liquid phase(TLP)bonding of GTD-111 superalloy were *** bonding process was applied using BNi-3 filler at temperatures of 1080,1120,and 1160℃ for isothermal solidification time of 195,135,and 90 min,*** heat treatment was also applied to all of the *** results show that intermetallic and eutectic compounds such as Ni-rich borides,Ni−B−Si ternary compound and eutectic-γcontinuously are formed in the joint region during *** increasing tJ,intermetallic phases are firstly reduced and eventually eliminated and isothermal solidification is completed as *** the increase of the holding time at all of the three bonding temperatures,the thickness of the athermally solidified zone(ASZ)and the volume fraction of precipitates in the bonding area decrease and the width of the diffusion affected zone(DAZ)*** results are also obtained by increasing TJ from 1080 to 1160℃ at tJ=90 ***,increasing the TJ from 1080 to 1160℃ leads to the faster elimination of intermetallic phases from the ***,these phases are again observed in the joint region at 1180℃.It is observed that by increasing the bonding temperature,the bonding width and the rate of dissolution of the base metal *** on these results,increasing the homogenization time from 180 to 300 min leads to the elimination of boride precipitates in the DAZ and a high uniformity of the concentration of alloying elements in the joint region and the base metal.

关键词： TLP bonding joint GTD-111 superalloy isothermal solidification microstructure homogenization

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Standard heat treatment effects on TLP bonded IN-738LC superalloy using BNi-9 filler:An approach to make an ideal joint

引用

Transactions of Nonferrous Metals Society of China 2022年第1期32卷 192-205页

作者： Danesh AMIRI Ata KAMYABI-GOL seyed abdolkarim sajjadi Department of Materials Science and Engineering Engineering FacultyFerdowsi University of MashhadMashhadIran

The present research is focused on the effects of standard heat treatment on the microstructure and mechanical properties of diffusion brazed IN-738 LC *** distinct heat treatment cycles of full solution annealing,partial solution annealing,and aging treatment were applied to the bonded specimens,*** results reveal that bonding at 1120℃for 5 min leads to incomplete isothermal solidification and formation of eutectic phases including Ni-and Cr-rich borides in the joint *** the holding time to 45 min leads to the full isothermal solidification and formation of a nickel proeutectic solid-solution phase(γ)in the *** standard heat treatment of isothermally solidified and non-isothermally solidified specimens results in the complete elimination of the boride phases in the diffusion-affected zone and also the formation ofγ’precipitates in the isothermally solidified ***,discontinuously re-solidified products are observed in joint district in the non-isothermally solidified *** highest shear strength(~801 MPa)is achieved for isothermally solidified specimen after standard heat treatment;this strength is approximately 99%that of the substrate material.

关键词： IN738LC standard heat treatment diffusion brazing isothermal solidification γ’precipitates mechanical properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Microstructural aspects of in-situ TiB reinforced Ti-6Al-4V composite processed by spark plasma sintering

引用

Transactions of Nonferrous Metals Society of China 2015年第5期25卷 1460-1467页

作者： Saeid GHESMATI TABRIZI Abolfazl BABAKHANI seyed abdolkarim sajjadi 吕维洁 Department of Materials Science and Engineering Engineering Faculty Ferdowsi University of Mashhad 上海交通大学材料科学与工程学院金属基复合材料国家重点实验室上海200240

Titanium-matrix composites have important and wide applications in the transport and aerospace industries. The current research was focused on powder metallurgy processing of in-situ reinforced titanium-matrix composite with Ti B whiskers. The Ti-6Al-4V alloy and B4 C additive powders were used as raw materials. Two different consolidation techniques, namely press-and-sintering and spark plasma sintering, were selected. It was observed that in-situ Ti B whiskers were formed during sintering in both methods. The changes in size, aspect ratio and distribution of in-situ whiskers in different composite samples were monitored. The effect of spark plasma sintering temperature on the synthesis of in-situ whiskers was also investigated. Based on the microstructural observations（optical microscopy and scanning electron microscopy） and the energy dispersive spectroscopy analysis, it was concluded that increasing the spark plasma sintering temperature from 900 to 1100 °C would lead to the complete formation of in-situ Ti B whiskers and reduced porosity content.

关键词： Ti-6Al-4V metal matrix composite TiB whisker in-situ reaction spark plasma sintering

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Evaluation of Characteristics of Interfacial Phases Produced in Al/Ni<sub>3</sub>Al Composite during Manufacturing

引用

Materials Sciences and Applications 2011年第9期2卷 1340-1348页

作者： seyed abdolkarim sajjadi Maryam Abbasi Mazyar Azadbeh 不详

Metal matrix composites (MMCs) are currently being investigated because of their superior properties. The properties are mainly attributed to the efficiency of the load transfer from the matrix to the reinforcements through the matrix-reinforcement interface. The aim of this study is to investigate the effect of manufacturing parameters on the microstructure and morphology of the interface and the aluminide phases formed at the matrix-reinforcement interfaces. The parameters are: milling time to fabricate Ni3Al, method of mixing of Ni3Al and Al powders, compaction pressure and sintering temperature. The composite studied in this research was Al/5 Vol% Ni3Al made from two different types of Ni3Al powders. The results showed that compacting and sintering at higher levels lead to the transformation of Ni3Al particles to thin layers of Al3Ni. It was also shown that the prolonged milling time to produceNi3Alreinforcements and the prolonged ball milling procedure for mixing the powders, both, promote the diffusion process at reinforcement/matrix interface.

关键词： Metal-Matrix Composites (MMCs) Interface X-Ray Diffraction (XRD) Powder Processing

来源：

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

Effect of Copper Content on Compressive Strength and Microstructure of Dental Amalgams

引用

Engineering（科研） 2012年第3期4卷 155-159页

作者： Akram Hasheminezhad seyed Mojtaba Zebarjad seyed abdolkarim sajjadi Laleh Rahanjam Ferdowsi University of Mashhad Mashhad Iran

The main goal of this research is to investigate the effect of copper on compressive strength of dental amalgam. For this purpose amalgam capsules with two different content of copper were used. Cylindrical samples with diameter to height ratio 1 to 2, were prepared via molding method. To evaluate the role of copper element on compressive strength, com-pression test was done at different strain rates i.e. 0.02, 0.2, 0.4 and 2 min–1. The results and microscopic evaluations showed that an increase in copper content in amalgam caused to eliminate gamma2 phase and leaded to promote compressive strength.

关键词： Amalgam Copper Compressive Strength Microstructure Gamma2

来源：

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

Investigation and Optimization of Sn/Gr Lubricants Effects on Cold Extrudability of Fe-TiC Nanocomposite Using Taguchi Robust Design Method

引用

Engineering（科研） 2011年第7期3卷 700-707页

作者： seyed abdolkarim sajjadi seyed Mojtaba Zebarjad Nasrin Sasani Heydar Khadivi Behrooz Naderi 不详

The present study deals with the effects of both tin (Sn) and graphite (Gr) powders on the cold extrudability of Fe-TiC nanocomposites as lubricant. The production process includes low-energy ball milling, powder metallurgy and cold direct Extrusion. Due to various factors influencing the extrudability of the Fe-TiC nanocomposites, such as milling time, rate of extrusion, type and content of lubricant and etc, Taguchi robust design method of system optimization was used to determine the approximate contribution percent (% ρ) of each factor. In order to investigation of Fe-TiC properties, samples with best quality of extrusion were analyzed by XRD and SEM investigations. The results indicate that, sitting the atomic layers of Sn lubricant between Fe and TiC particles leads to decreasing the friction. In this case sliding the particles on each other is easier and a part of the load is applied on lubricant. The results of extrusion of samples indicate that using 2% Sn admixed and die wall graphite lubrication can improve cold extrudability of Fe-TiC nanocomposites.

关键词： Extrudability Fe-TiC Lubricant Nanocomposite Taguchi Robust Design Method

来源：

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

Geochemistry and provenance of the lower-middle pliocene cheleken formation,Iran

引用

Acta Geochimica 2021年第5期40卷 787-805页

作者： Houshang Mehrabi seyed Mohammad Zamanzadeh Abdolhossein Amini Vahid Tavakoli Freshteh sajjadi seyede Sepideh Mirrabie Behzad Soltani Academic Center for Education Culture and Research(ACECR)Tehran 19839694Iran School of Geology College of SciencesUniversity of TehranTehranIran

In the present study,the Lower-Middle Pliocene Cheleken Formation in the south of Ghaemshahr city was studied to determine the provenance of the comprising sediments,paleoclimatic conditions,and tectonic setting of the *** and geochemical analyses of major and minor elements of the samples were used for this *** Formation is composed of three major facies including conglomerate,fine sandstone,and *** source formations which were recognized to be supplying sediments to the Cheleken Formation depositional basin include Lalun,Ziarat,Tizkuh,Dalichai,and Cretaceous *** to the discrimination diagrams and other ratios for minor elements of the studied samples,a complex of felsic to intermediate igneous rocks in the source region was *** depositional environment of the rocks experienced humid and semi-arid climatic conditions during *** to the CIW index,the samples underwent a high level of weathering(97%)in the source area or during *** a tectonic point of view,the Cheleken Formation was deposited in an Active Continental Margin setting.

关键词： Geochemistry Provenance Cheleken formation Pliocene Caspian sea

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Impact of Die Materials on the Effect of New Polymer Processing Aids for Sharkskin Properties

引用

Journal of Materials Science and Chemical Engineering 2016年第9期4卷 17-27页

作者： seyed Pooyan sajjadi Polymertechnik/Polymerphysik Technische Universit at Berlin Berlin Germany

Flows of polymeric liquids undergo instabilities whose origins are quite different from those of Newtonian flows, due to their elastic character and the complexity of the fluid/solid boundary condition. One of these instabilities is well known as “shark-skin” which damages the surface appearance and properties of polymer extrudate while processing in blowmolding or piping, while it can be suppressed by employing various methods including coating the die surface and/or adding Polymer Processing Aid’s (PPA) to the polymer. In this article, the effect of various die materials on the properties of Polyethylene glycol (PEG) as a new type of PPA for suppressing the sharkskin phenomenon has been studied.

关键词： Polymer Processing Aids (PPA) PEG Sharkskin Extrusion Instabilities

来源：

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

Factor XIII VaU34Leu polymorphism and risk of recurrent pregnancy loss in Iranian population： a case control study

引用

Frontiers in Biology 2016年第6期11卷 471-475页

作者： seyed Mehdi sajjadi Abbas Khosravi Jalil Pakravesh Zahra-soheila Soheili Shahram Samiei Saeed Mohammadi Mohammad Ali Jalali far Cellular and Molecular Research Center of Birjand University of Medical Sciences Biriand Iran Department of Hematology Tehran University of Allied Medical Sciences Tehran Iran Department of Obstetrics and Gynecology Aban General Hospital Tehran Iran Cellular and Molecular Biology National Institute of Genetic Engineering and Biotechnology Tehran Iran Blood Transfusion Research center High Institute for Research and Education in Transfusion Medicine Tehran Iran Hematology Oncology and Stem Cell Translantation Research Center Tehran University of Medical Sciences Tehran Iran Health research institute Research Center of Thalassemia & Hemoglobinopathy Ahvaz Jundishapur University of Medical Sciences AhvazIran

BACKGROUND： Recurrent pregnancy loss （RPL） is a heterogeneous condition and thrombophilias have been considered as a probable cause. OBJECTIVE： The aim of this study was to investigate the prevalence of the coagulation factor XIII Va134Leu polymorphism among women with unexplained RPL. METHODS： A total of 140 women with a history of unexplained RPL and 100 age-matched healthy fertile women were recruited. The presence of FXIII Va134Leu polymorphism among the cases and controls was investigated using PCR-RFLP method. RESULTS： Genotype analyses of the subjects revealed that the patients had a significantly higher prevalence of V/L and L/L than the controls （P〈 0.05）： 33.5% vs. 15%, and 9.2% vs. 2%, respectively. CONCLUSION： These results indicate a significant association between FXIII Va134Leu polymorphism and unexplained RPL in the Iranian patient.

关键词： factor XIII Iranian population recurrent pregnancy loss Va134Leu polymorphism

来源：

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

Cryptanalysis and improvement of two new RFID protocols based on R-RAPSE

引用

Journal of Communications and Information Networks 2017年第3期2卷 107-122页

作者： seyed Salman sajjadi GhaemMaghami Afrooz Haghbin Mahtab Mirmohseni Department of Computer Engineering Science and Research branchIslamic Azad UniversityTehran ***Iran Department of Electrical Engineering Sharif University of TechnologyTehran 11365/8639Iran

RFID(Radio Frequency IDentification)is a pioneer technology which has depicted a new lifestyle for *** we observe an increase in the number of RFID applications and no one can ignore their numerous *** important issue with RFID systems is providing privacy requirements of these systems during *** in 2014,Cai et *** two improved RFID authentication protocols based on R-RAPS(RFID Authentication Protocol Security Enhanced Rules).We investigate the privacy of their protocols based on Ouafi and Phan privacy model and show that these protocols cannot provide private authentication for RFID ***,we show that these protocols are vulnerable to impersonation,DoS and traceability ***,we present two improved efficient and secure authentication protocols to ameliorate the performance of Cai et al.’s *** analysis illustrates that the existing weaknesses of the discussed protocols are eliminated in our proposed protocols.

关键词： authentication RFID protocol privacy security Ouafi Phan privacy model traceability impersonation

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：