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Processing of Ceramic Based Nanocomposite Usingα-Al_2O_3 Powder and FeCl_2 Solution as Starting materials

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Journal of materials Science & Technology 2007年第6期23卷 837-842页

作者： mohamed m.EL-Sayed seleman Department of materials and metallurgical Engineering Faculty of Petroleum and Mining EngineeringPost Code 43721SuezEgypt

Alumina-iron nanocomposite powders were prepared by a two-step process. In the first step, α-Al2O3-FeCl2 powder mixture was formed by mixing α-Al2O3 powders with FeCl2 solution followed by drying. In the second step, the FeCl2 in the dry power mixture was selectively reduced to iron particles. A reduction temperature of 750℃ for 15 min in dry H2 was chosen based on the thermodynamic calculations. The concentration of iron in FeCl2 solution was calculated to be 20 vol. pct in the final composite. Two techniques were used to produce composite bulk materials. The Al2O3 nanocomposite powders were divided to two batches. The first batch of the produced mixture was hot pressed at 1400℃ and 27 mPa for 30 min in a graphite die. To study the effect of oxygen on the Al2O3/Fe interface bonding and mechanical properties of the composite, the second batch was heat treated in air at 700℃ for 20 min to partially oxidize the iron particles before hot pressing. Characterization of the composites was undertaken by conventional density measurements, X-ray diffractometry （XRD）, scanning electron microscopy （SEm）, transmission electron microscopy （TEm） and electron probe micro analysis （EPmA）. The suggested processing route （mixing, reduction and hot pressing） produces ceramic-metal nanocomposite much tougher than the pure Al2O3. The fracture strength of the produced Al2O3/Fe nanocomposite is nearly twice that of the pure Al2O3. The presence of spinel phase, FeAl204, as thick layer around the Fe particles in the Al2O3 matrix has a detrimental effect on interfacial bonding between Fe and AI203 and the fracture properties of the composite.

关键词： Ferrous chloride Reduction Alumina-iron nanocomposite Spinel phase

Effects of Nickel Distribution on the Strengthening and Toughening of Alumina Ceramics

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Journal of materials Science & Technology 2008年第5期24卷 723-728页

作者： mohamed.m.El-Sayed seleman Department of materials and metallurgical Eng. Faculty of Petroleum and Mining Eng.Post Code 43721SuezEgypt

Three types of composite materials were designed and fabricated by hot pressing powder blends of alumina with 20 vol. pct nickel particles. The composites differ in the shape, size and distribution of the nickel particles. Composite microstructures are described and measurements of density, hardness, flexure strength, and fracture toughness are reported. The results showed that the fracture strength of the composite with dispersed nickel particles is higher than the other two composites （network microstructure and mixed microstructure） and the alumina matrix. For all the composites studied, tougher materials than the monolithic alumina were produced. The fracture toughness of the composite with a network microstructure is much higher than that of the other composites. The toughening mechanisms were described based on the observation of the fracture surfaces and the crack-particle interactions. moreover, the parameters for microstructural tailoring of these materials have been deduced. The toughening of the produced composites was explained in light of the interracial bond strength.

关键词： Alumina-nickel composites Nickel morphology Interfacial bonding Fracturetoughness Flexure strength

microstructure and mechanical properties of hot extruded 6016 aluminum alloy/graphite composites

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Journal of materials Science & Technology 2018年第9期34卷 1580-1591页

作者： mohamed m.El-Sayed seleman mohamed m.Z.Ahmed Sabbah Ataya Department of metallurgical and materials Engineering Faculty of Petroleum and Mining Engineering Suez University 43518 Suez Egypt Suez and Sinai metallurgical and materials Research Center of Scientific Excellence (SSmmR-CSE) 43518 Suez Egypt The British University in Egypt Mechanical Engineering Deportment El-Sherouk City 11837 Cairo Egypt Department of mechanical Engineering College of Engineering AI Imam Mohammad Ibn Saud Islamic University Riyadh 11432 saudi Arabia

The incorporation of graphite particles into AA6016 aluminum alloy matrix to fabricate metal/ceramic composites is still a great challenge and various parameters should be considered. In this study, dense AA6016 aluminum alloy/（0-20 wt%） graphite composites have successfully been fabricated by powder metallurgy process. At first, the mixed aluminum and graphite powders were cold compacted at 200 mPa and then sintered at 500 ℃ for 1 h followed by hot extrusion at 450 ℃. The influence of ceramic phases（free graphite and in-situ formed carbides） on microstructure, physical and mechanical properties of the produced composites were finally investigated. The results show that the fabricated composites have a relative density of over 98%. SEm observations indicate that the graphite has a good dispersion in the alloy matrix even at high graphite content. Hardness of all the produced composites was higher than that of aluminum alloy matrix. No cracks were observed at strain less than 23% for all hot extruded *** strength, reduction in height, ultimate tensile stress, fracture stress, yield stress, and fracture strain of all Al/graphite composites were determined by high precision second order equations. Both compressive and ultimate tensile strengths have been correlated to microstructure constituents with focusing on the in-situ formed ceramic phases, silicon carbide（SiC） and aluminum carbide（Al4 C3）. The ductile fracture mode of the produced composites became less dominant with increasing free graphite content and in-situ formed carbides. Wear resistance of Al/graphite composites was increased with increasing graphite content. Aluminum/20 wt% graphite composite exhibited superior wear resistance over that of AA6016 aluminum alloy.

关键词： AA6016/graphite composites Hot extrusion In-situ carbides mechanical properties Wear resistance Fracture behavior

Strength and Wear Behavior of mg Alloy AE42 Reinforced with Carbon Short Fibers

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Acta metallurgica Sinica(English Letters) 2019年第1期32卷 31-40页

作者： Sabbah Ataya Naser A.Alsaleh mohamed m.El-Sayed seleman metallurgical and materials Engineering Department Faculty of Petroleum and Mining Engineering Suez University Department of mechanical Engineering College of Engineering Al Imam Mohammad Ibn Saud University

In addition to the advantage of the lightweight of magnesium alloys, magnesium composites have moderate strength and elastic modulus. The proposed application of magnesium composites as diesel truck pistons makes it necessary to assess their wear performance. Little research data have been discussed on wear behavior of mg alloy AE42 matrix and its composites. Thus, this paper reports wear behavior of magnesium alloy AE42(mg–Al–mn—RE; rare earth) and its composite AE42-C, which contains 23 vol% of randomly oriented carbon short fibers. materials characterization, including density measurements, hardness testing, microstructures investigation, and compression testing at temperatures of 25, 150,and 300 °C, were conducted. Wear tests were performed under various loads and sliding distances. Wear mechanisms were also proposed based on the examination of worn surfaces using optical microscopy and scanning electron microscopy equipped with EDX(energy-dispersive X-ray spectrometry) analysis system. The hardness of AE42-23 vol% C composite is twice the hardness of the mg matrix alloy AE42. Significant improvements to yield stress and compressive strength at temperatures of 25, 150, and 300 °C of the composite versus the AE42 alloy are achieved. Wear resistance of the composite is improved considerably versus that of the mg alloy AE42 at the various sliding distances. Smearing of graphite on the worn surface produces a lubricating film that delays change from mild to severe wear of the composite, especially at high loads. EDX analysis of the worn surface shows oxidation of the matrix alloy at higher wear loads, and this mechanism decreases in the presence of carbon fibers under the same loads. Abrasive wear, oxidation, and plastic deformation are the dominant wear mechanisms for the alloy matrix AE42, whereas mainly abrasive wear is the wear mechanism of AE42-23 vol% C composite under the proposed testing conditions.

关键词： magnesium composites Carbon short fibers Compressive strength Wear resistance Wear mechanisms

Review on friction stir welding of dissimilar magnesium and aluminum alloys: Scientometric analysis and strategies for achieving high-quality joints

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Journal of magnesium and Alloys 2023年第11期11卷 4082-4127页

作者： mohamed m.Z.Ahmed mohamed m.El-Sayed seleman Dariusz Fydrych Gürel ÇAm Department of mechanical Engineering College of Engineering at Al KharjPrince Sattam Bin Abdulaziz UniversityAl Kharj 11942Saudi Arabia Department of metallurgical and materials Engineering Faculty of Petroleum and Mining EngineeringSuez UniversitySuez 43512Egypt Faculty of mechanical Engineering and Ship Technology Institute of Machines and Materials TechnologyGdańsk University of TechnologyGabriela Narutowicza Street 11/12Gdańsk 80-233Poland Department of mechanical Engineering Iskenderun Technical UniversityIskenderunHatay 31200Turkiye

magnesium and aluminum alloys continually attract interest as lightweight structural materials for transport applications. However, joining these dissimilar alloys is very challenging. The main obstacle that hinders progress in dissimilar mg-Al joining is the formation of brittle intermetallic compounds(ImCs). As a solid-state joining technique, FSW is an excellent candidate to attenuate the deleterious ImC effects in dissimilar Al-mg joining due to the inherent low heat inputs involved in the process. However, the ImCs, namely Al_(3)mg_(2) and Al_(12)mg_(17) phases, have also been reported to form during Al-mg dissimilar FSW;their amount and thickness depend on the heat input involved;thus,the weld parameters used. Since the heat dissipated in the material during the welding process significantly affects the amount of ImCs,the heat input during FSW should be kept as low as possible to control and reduce the amount of ImCs. This review aims to critically discuss and evaluate the studies conducted in the dissimilar Al/mg FSW through a scientometric analysis and also with a focus on the strategies recently applied to enhance joint quality. The scientometric analysis showed that the main research directions in mg/Al FSW are the technological weldability of aluminum and magnesium during FSW, structural morphology, and mechanical properties of dissimilar welded joints. Considering the scope of application of the aforementioned joints, the low share of articles dealing with environmental degradation and operational cracking is surprising. This might be attributed to the need for well-developed strategies for obtaining high-quality and sustainable joints for applications. Thus, the second part of this review is conventional, focusing mainly on the new strategies for obtaining high-quality mg/Al joints. It can be concluded that in addition to the necessity to optimum welding parameters to suppress the excessive heat to limit the amount and thickness of ImC formed and improv

关键词： Friction stir welding(FSW) Al-alloys mg-alloys Dissimilar material welding Intermetallics Weld performance

Thermal Shock Behaviour of Alumina-Iron Composites

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Journal of materials Science & Technology 2002年第4期18卷 347-350页

作者： m.m.El-Sayed seleman, Xudong SUN and Liang ZUOSchool of materials and metallurgy, Northeastern University, Shenyang 110006, China Sch. of mat. and metall. Northeastern Univ. Shenyang 110006 China

Thermal shock behaviour was investigated for two morphologically different composites comprising an alumina matrix and 20 vol. pct Fe particles for a wide range of quenching temperature differences (AT=100~800癈) and compared to a monolithic alumina. The retained strength and critical quenching temperature difference, Tcr of the two composites were a significant improvement over the values for the respective monolithic alumina. Crack lengths and densities were shown to be greater for the alumina than for the two composites at all quenching temperature differences. The thermal shock resistance parameters for monolithic alumina and the two composites were calculated according to their mechanical and physical properties. The calculated results agree well with the experimental one and indicate possible explanations for the differences in thermal shock behaviour.

关键词： Alumina-iron composite thermal shock behaviour Retained strength

Properties of Hot-Pressed Al_2O_3-Fe Composites

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Journal of materials Science & Technology 2001年第5期17卷 538-542页

作者： m.m.El-Sayed seleman, Xudong SUN and Liang ZUO Department of materials Science and Engineering, Northeastern University, Shenyang 110006, China K.A.Khalil Powder metallurgy Institute, Central South University, Changsha 410083, China Dept. of mat. Sci. and Eng. Northeastern Univ. Shenyang 110006 China

Alumina-(0 similar to 20 vol. pct) iron composites were fabricated by hot-pressing of well-mixed-alumina and iron powders at 1400 degreesC and 30 mPa for 30 min. Hot-pressed bodies with nearly theoretical density were obtained for addition up to 10 vol. pct Fe, but relative density decreased gradually with further increase in Fe addition. The materials exhibit a homogeneous dispersion of Fe. Fracture strength of the composites exhibits a maximum value of 604 mPa at 15 vol. pct Fe, which is 1.5 times that of alumina alone. Fracture toughness increases with the increase in Fe content, reaching 7.5 mPa.m(1/2) at 20 vol. pct Fe. The theoretical values of fracture toughness was calculated and compared with the experimental one. Toughening mechanisms of the composites are also discussed.

关键词： Fe Properties of Hot-Pressed Al2O3-Fe Composites Al

Comparison between the Requirements of Flowability and moldability and the Shape Retention of PIm Compacts during Debinding Process

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Journal of materials Science & Technology 2001年第5期17卷 490-494页

作者： K.A.KhaliI, Baiyun HUANG and Yimin LI State Key Laboratory for Powder metallurgy, Central South University, Changsha 410083, China m.m.El-Sayed seleman Department of materials Science and Engineering, Northeastern University, Shenyang 110006, China State Key Lab. for Powder metall. Central South Univ. Changsha 410083 China

To successfully employ powder injection molding (PIm) as a manufacturing technique, the function of the component, design of the part, material and process should be optimized for overall processing ability of the PIm process. A comparison between the requirements of flowability and moldability and the compacts shape retention has been made in this work. There is often a contradiction between the requirements of flowability and the compacts shape retention. many works have been done to attain good molding conditions. However, they fail to take into account the effect of some factors that satisfies good molding conditions on the compacts shape retention during debinding. This paper studies the effect of the powder-binder mixture characteristics and the molding conditions on the flowability and moldability and the shape retention of PIm compacts during debinding process so as to attain the benefits of each.

关键词： PIm Comparison between the Requirements of Flowability and moldability and the Shape Retention of PIm Compacts during Debinding Process