Joining of Steel-Aluminium Hybrid Structures with Electron Beam on Atmosphere

2005 ◽  
Vol 6-8 ◽  
pp. 143-150 ◽  
Author(s):  
Friedrich Wilhelm Bach ◽  
A. Beniyash ◽  
K. Lau ◽  
R. Versemann

Against the background of the required weight reduction in transportation through lightweight construction, the application of hybrid structures, where dissimilar materials are joined together, has a high technical and economical potential. In the field of sheet machining, combinations of steel and aluminium are especially interesting. In comparison to conventional steels, the application of aluminium alloys as supporting materials makes a distinct weight reduction possible. On the other hand, steels have advantages in the fields forming and welding. The application of modern high-strength steels with reduced sheet thicknesses allows weight reduction, too. But joining of material combinations of steel and aluminium is problematic. On the one hand brittle intermetallic compounds are formed between steel and aluminium. On the other hand the aluminium melt has a bad wetting behaviour. Different physical properties of both materials have to be considered, too. To achieve sufficient mechanical properties of such joinings it is necessary to limit growth of intermetallic compounds between steel and aluminium. This can be actualized by an exact energy supply. With the electron beam on atmosphere a precise and easily controllable energy supply is possible. The publication demonstrates successful investigations, which were performed with the 175 kVNVEBW (Non Vacuum Electron Beam Welding) installation at Institut of Materials Science, University of Hanover. With NVEB joining hybrid structures between zinc coated steels and 5.xxx and 6.xxx aluminium alloys were produced. In a welding-brazing process (the steel remained in the solid phase whereas the aluminium was molten) combinations with acceptable mechanical properties could be joined. By use of optimized joining parameters as well as a surface activating flux, both, a good wetting and a thin intermetallic compound < 10 µm were attained. Another possible strategy is a pure brazing process, for which an example is also given in the paper. The paper shows metallurgical and mechanical investigations, among other things results of element distribution analysis and tensile tests.

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Koh-hei Nitta ◽  
Yoshikazu Yamamoto

Abstract We examined mechanical and morphological properties of fully transcrystalline polypropylene grown from the surface of poly(tetrafluoroethylene) sheets. Comparison of mechanical properties between transcrystalline and spherulitic polypropylenes demonstrated that Young’s modulus is dependent on the crystallinity and independent of the supermolecular structure. On the other hand, the mechanical yielding process was predominantly affected by the supermolecular structure, and the mechanical energy required for yielding of transcrystalline sheets was greater than that of the spherulitic morphology. In addition, it was found that mechanical necking is required for the alignment of lamellae in the stretching direction. This means that the unfolding process of lamellae orienting in the stretching direction is associated with necking and ductility.


1931 ◽  
Vol 4 (1) ◽  
pp. 54-63
Author(s):  
H. Mark ◽  
E. Valko

Abstract It is only during recent years that it has become possible by the use of new technic to detect molecular phenomena produced in the mechanical deformation of substances. As far as metallic substances are concerned, and crystalline substances in particular, the problem has already been solved for the most part. On the other hand, in spite of considerable progress during recent years the study of the deformation of organic substances and of fibers in particular, in which group rubber is included, has not yet been carried on. The mechanical properties of a crystalline system vary according to whether there is a single crystal or an aggregate of crystals. However, in both cases the extensibility of the products originates in a displacement of parallel layers, i. e., a sliding of the parts of the crystal along definite crystalline planes, this phenomenon of sliding being irreversible in these substances. In fact, in these cases the reversible part of the elongation is very weak, and amounts to only a few thousandths of the entire phenomenon. In brief, the phenomena of hardening brought about by deformation (sometimes observable) are due to disturbances of the regular lattice. In particular, the displacement of the atom and the change from its normal position can cause the appearance of irregularities on the surface of sliding.


2014 ◽  
Vol 699 ◽  
pp. 169-174
Author(s):  
Achmad Zubaydi ◽  
Nurul Muhayat ◽  
Budie Santosa ◽  
Dony Setyawan

Double sided friction stir butt welds on 6 mm thick of 5083 aluminum alloy were produced. Two variants of the weld side combination, different weld side (DS) and same weld side (SS), have been made to investigate the effect of the weld side on mechanical properties.The SS is a double sided welding process that produces advancing side in one plate and retreating side in the other one. On the other hand, the DS is a double sided welding process that causes advancing side and retreating side in each plate. Tensile properties of the joints were evaluated and correlated with macrostructure and hardness. The weld side influenced the macrostructure and mechanical properties of welded joints. The different weld side (DS) had better mechanical properties than the same weld side (SS).


2015 ◽  
Vol 815 ◽  
pp. 164-169
Author(s):  
Ng Hooi Jun ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Husin ◽  
Soo Jin Tan ◽  
Mohd Firdaus Omar

Utilization and suitability of bottom ash in Portland cement have been increasing significantly in recent year. Bottom ash has substantial effects on mechanical properties with different composition of replacement in mixture of bottom ash and Portland cement. Bottom ash was used to determine the feasibility of the substitution as recycling product from industry depending on the percentage of the bottom ash. On the other hand, bottom ash offers a better solution for maintaining materials characteristic of Portland cement mortar and also provide beneficial mechanical performance. The result of using bottom ash in Portland cement mortar showed that it could make better the mechanical properties and hence disposed bottom ash wastes safely in technical, economic and environmental methods.


2018 ◽  
Vol 56 (2A) ◽  
pp. 63-68
Author(s):  
Le Thi Bang

Bis-3,4- dimethyldibenzylidene sorbitol (DMDBS); bis-p-methylbenzylidene sorbitol (MDBS) and the mixture of DMDBS/MDBS (50/50) were studied through optical, thermal, mechanical properties and surface morphology. With the same amount of additive (DMDBS/MDBS mixture and DMDBS) in the material, the results are similar. On the other hand, using an additive mix reduces the cost of production due to MDBS. Furthermore, the additive mixture is used without producing odours. Therefore, the mixture of DMDBS/MDBS (50/50) is chosen.


2020 ◽  
Vol 10 (24) ◽  
pp. 9016
Author(s):  
Ibrahim A. Al-Hawas ◽  
Salah A. Hassan ◽  
Hany M. AbdelDayem

In this work, various physicochemical characteristics, e.g., surface properties and mineralogical compositions, of five clays collected from different sites in the Al-Hasa oasis in Saudi Arabia have been investigated. Analysis of the mineralogical compositions of the clays in the study by X-ray diffraction indicated the coexistence of palygorskite, montmorillonite, illite, kaolinite, chlorite, calcite and quartz in different percentages. Thermogravimetric analysis indicated that all studied clays exhibited dehydroxylation temperatures higher than 470 °C. On the other hand, pore size distribution analysis of clays from N2 adsorption indicated the presence of micro- and narrow mesopores (of 1.3–2.8 nm). Furthermore, the capability of the different clays for removal of Pb (II) from aqueous solution has been studied. The adsorption process was described through the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich models. The Langmuir model was the most suitable compared to the other models in the case of palygorskite- and montmorillonite-rich clays. However, the Temkin model better represented the adsorption process of Pb (II) on calcite-rich clay. The clay sample with 61.0 wt% of palygorskite was found to be the most effective at removing Pb (II), with a maximum removal capacity of 74.07 mg/g at pH 6, with a contact time of 6 h and at 25 °C. Generally, the adsorption mechanism of lead over all the studied clays followed the pseudo-second-order kinetics. On the other hand, the catalytic activity of clays in the study has been tested in methanol conversion. The acidic clays, those containing high amounts of montmorillonite, showed higher selectivity to ethylene, viz., 78.9%, with a methanol conversion of 39.1% at 350 ° C and 0.1 MPa.


2020 ◽  
Vol 4 (1) ◽  
pp. 17 ◽  
Author(s):  
Akihiro Iwase ◽  
Fuminobu Hori

When materials are irradiated with high-energy ions, their energies are transferred to electrons and atoms in materials, and the lattice structures of the materials are largely changed to metastable or non-thermal equilibrium states, causing the modification of several physical properties. There are two processes for the material modification by ion irradiation; one is “the irradiation-enhanced process”, and the other is “the irradiation-induced process”. In this review, two kinds of recent results for the microstructural changes and the modifications of mechanical properties will be summarized: one is the hardness modification of dilute aluminum alloys, which is a result of the irradiation-enhanced process, and the other is the hardness modification of Ni-based intermetallic compounds as a result of the irradiation-induced process. The effect of the subsequent thermal treatment on the microstructures and the hardness for ion-irradiated dilute aluminum alloys is quite different from that for Ni-based intermetallic compounds. This result reflects the difference between the irradiation-enhanced process and the irradiation-induced process. Finally, possibilities of the ion irradiation and subsequent thermal treatment to industrial applications will also be discussed.


2011 ◽  
Vol 250-253 ◽  
pp. 480-484 ◽  
Author(s):  
Miao Zhou Huang ◽  
Tao Meng ◽  
Xiao Qian Qian ◽  
Jin Jian Zhang

The flow ability, mechanical properties and microstructure of concrete with different strength grades affected by nano-SiO2and nano-CaCO3was studied. The experiment results showed that the strength of concrete at early age was increased by adding the nano-materials if the strength grade of concrete was not high. But the strength at the age of 28 days was not affected a lot by adding these nano-materials. On the other hand, it was not useful to the strength if the strength grade of concrete was high.


The author points out what he considers to be important errors in the series of papers by Dr. Martin Barry, which have lately appeared in the Philosophical Transactions, and are entitled, “ On the Corpuscles of the Blood ," and “ On Fibre ." He alleges that Dr. Barry has generally confounded the colourless corpuscles contained in the blood with the red corpuscles of the same fluid; each of which latter kind consists of a vesicle or cell, with thick walls, but in a collapsed and flattened state, and having therefore a biconcave form, and in consequence of its thick wall being doubled on itself, presenting under the microscope a broad circumferential ring, which is illuminated or shaded differently from the depressed central portion, according to the focal adjustment of the instrument: while the colourless corpuscles, on the other hand, are of a globular shape, strongly refractive of light, and granulated on their surface, and are of less specific gravity and of somewhat larger size than the red corpuscles. The author quotes various passages from Dr. Barry’s papers in proof of his assertions, and refers particularly to fig. 23 of his second paper on the corpuscles of the blood. He farther states, that Dr. Barry’s description of the appearances of what he terms the red corpuscles, in paragraphs 53, 68, and 76 of his second paper, can, in fact, apply only to the colourless corpuscles: and he observes, that even when Dr. Barry does, at last, in his “Additional Observations,” advert to the distinction between the red and the colourless globules, he considers the latter as being merely “the discs” contained in the red globules appearing under an altered state. The author regards as wholly erroneous the notion which Dr. Barry entertains that a fibre exists in the interior of the blood-cor­puscle; and that these fibres, after their escape from thence, constitute the fibres which are formed by the consolidation of the fibrin of the liquor sanguinis . The beaded aspect presented by the double contour of the thick wall of the red corpuscle when it has been acted upon either by mechanical causes or by chemical reagents, of which the effect is to corrugate the edge, and to bend it alternately in opposite directions, has, in the opinion of the author, given rise to the illusive appearance of an internal, annular fibre. The appearance of flask-like vesicles presented by some of the red corpuscles, with the alleged fibre protruding from their neck, the author ascribes altogether to the effects of decomposition, which has altered the mechanical properties of the corpuscle, and allowed it to be drawn out, like any other viscid matter, into a thread.


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