scholarly journals Adhesive Properties of Metals and Metal Alloys

10.5772/60599 ◽  
2015 ◽  
Author(s):  
Anna Rudawska
Author(s):  
MQ dos Reis ◽  
RJC Carbas ◽  
EAS Marques ◽  
LFM da Silva

The development of lighter structures and materials has been one of the main research concerns of the transportation industry during the last decade, driven by the necessity to decrease fuel consumption and emissions. Therefore, the use of several different new lightweight materials, such as special metal alloys, reinforced polymers and new advanced composite materials has been explored, leading to optimized structures which combine these novel materials. To manufacture these multi-material structures, adhesive bonding is one of best joining techniques available, as fasteners add weight to the structure and require holes to be drilled and welding is not easily applicable to reinforced plastics, composites and some high strength metal alloys. However, adhesive bonding also presents some limitations that need to be considered, such as the appearance of singularities and the resultant stress concentration at the edges of the bond line, which result in a reduction of the joint strength. In order to mitigate this effect, several techniques have been proposed, being the use of functionally graded adherends one of them. Functionally graded adherends consist in an adherend where the mechanical properties gradually change throughout the material, usually in the thickness or length direction. The present work introduces the concept of a layered functionally graded adherend, varying the flexibility of each layer through the thickness direction. Different ratios of stiffness variation, combined with different adhesive properties, were numerically evaluated for single lap joints, comparing the stress distribution of the adhesive layer and the resultant joint strength, using cohesive zone modelling. Moreover, an optimization process of typical graded material properties, where different distribution laws that consider material weight and strength are considered, is presented.


2012 ◽  
Vol 727-728 ◽  
pp. 186-189 ◽  
Author(s):  
Jaqueline Dias Altidis ◽  
Silvio Romero de Barros ◽  
João Dellonx Régis Barboza de Souza ◽  
Sandro Marden Torres ◽  
Severino Jackson Guedes de Lima

The composite studied here consisted of a geopolymer matrix reinforced with quasicrystal powders. Quasicrystals are complex metal alloys with atypical structures. Due to their physical, mechanical and surface properties, quasicrystals have been widely studied. Nowadays quasicrystalline powders are proposed to be incorporated in ductile matrices. The geopolymers are inorganic polymers with excellent thermal performance and interesting adhesive properties. The quasicrystalline alloys were prepared by induction melting the constituents under argon atmosphere in a water-cooled copper crucible. In this work the adhesion of composites with 5, 10 and 15% of quasicrystal powder in aluminum joints was investigated. In addition, the influence of the curing time was taken in to account and tests were performed in samples with 7 and 28 days of cure. The results indicate an improvement in adherence with the inclusion of quasicrystal. The best adherence was obtained when the curing time was 28 days.


Author(s):  
K. F. Russell ◽  
L. L. Horton

Beams of heavy ions from particle accelerators are used to produce radiation damage in metal alloys. The damaged layer extends several microns below the surface of the specimen with the maximum damage and depth dependent upon the energy of the ions, type of ions, and target material. Using 4 MeV heavy ions from a Van de Graaff accelerator causes peak damage approximately 1 μm below the specimen surface. To study this area, it is necessary to remove a thickness of approximately 1 μm of damaged metal from the surface (referred to as “sectioning“) and to electropolish this region to electron transparency from the unirradiated surface (referred to as “backthinning“). We have developed electropolishing techniques to obtain electron transparent regions at any depth below the surface of a standard TEM disk. These techniques may be applied wherever TEM information is needed at a specific subsurface position.


1993 ◽  
Vol 90 ◽  
pp. 249-254 ◽  
Author(s):  
C Wolverton ◽  
M Asta ◽  
S Ouannasser ◽  
H Dreyssé ◽  
D de Fontaine

2015 ◽  
Vol 2 (1) ◽  
pp. 30-34
Author(s):  
K. Korobkova ◽  
V. Patyka

Contemporary state of the distribution of mycoplasma diseases of cultivated crops in Ukraine was analyzed. The changes of the physiological state of plant cells under the impact of mollicutes were investigated. It was demonstrated that there is temporary increase in the activity of peroxidase, catalase, polyphenoloxidase, phenylalanine-ammonia-lyase at the early stages of interaction. The adhesive properties are changed in the mollicutes under the impact of plant lectin; there is synthesis of new polypeptides. It was determined that the phytopathogenic acholeplasma is capable of producing a complex of proteolytic enzymes into the culture me- dium. It was concluded that when plant cells are infected with acholeplasma, a number of signaling interactions and metabolic transformations condition the recognition of pathogenesis and ensure the aggregate response of a plant to stress in the form of defense reactions. It was assumed that some specifi cities of the biology of phy- topathogenic acholeplasma determine their avoiding the immune mechanisms of plants and promote long-term persistence of mollicutes.


2012 ◽  
pp. 120409100715007
Author(s):  
JAINI J L ◽  
SREEKANTH A MALLAN ◽  
MURUKAN P. A ◽  
RITA ZARINA

2007 ◽  
Vol 22 (2) ◽  
pp. 333-342 ◽  
Author(s):  
Piotr Gołek ◽  
Włodzimierz Bednarski ◽  
Monika Lewandowska
Keyword(s):  

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