Improvement of mechanical properties in epoxy adhesive joints of Al alloy via carbon nanotubes from flame

2019 ◽  
Vol 6 (8) ◽  
pp. 0850d7 ◽  
Author(s):  
Pu Zhao ◽  
Xuhai Xiong ◽  
Rong Ren ◽  
Zhongbao Zhang ◽  
Xu Cui ◽  
...  
2022 ◽  
Vol 3 (1) ◽  
pp. 64-77
Author(s):  
Anna Rudawska ◽  
Magd Abdel Wahab ◽  
Miroslav Müller ◽  
Dana Stančeková

This paper presents issues related to the determination of the selected mechanical properties of adhesive joints made of polymeric pipes and the evaluation of the leak-tightness of the adhesive joints. The article attempts to demonstrate that the type of adhesive may affect the quality of adhesive joints in terms of both tightness and strength of joints. Five types of the polymer pipes differing in a polypropylene and a polyvinyl chloride, diameter and a wall thickness were used in the experiments. Two types of the adhesives were used to make the adhesive joints: Loctite 3430 A&B Hysol, a two-component epoxy adhesive, and Loctite 406, a one-component cyanoacrylate adhesive. Based on the leak-tightness tests results, it was possible to determine the quality of their adhesive joints without damaging the samples, while their tensile strength was determined through the strength tests. The tests performed allowed for the conclusion that the use of the polyvinyl chloride pipes and Loctite 406 one-component adhesive is recommended for this type of adhesive joints.


2021 ◽  
Vol 2 (1) ◽  
pp. 108-126
Author(s):  
Anna Rudawska

The article presents the issues of the mechanical properties of epoxy adhesives and the adhesive joints strength of steel sheets which were made using the epoxy adhesives. The aim of the paper is to study the mechanical properties of epoxy adhesive of different epoxy resin/curing agent ratios (within and above the recommended stoichiometric ratio) and their effect on mechanical properties of adhesive joints of steel sheets. In experimental tests three types of epoxy adhesives, containing a low molecular weight epoxy resin based on bisphenol A and polyamide curing agent, were used. A single-lap adhesive joint type of stainless-steel sheets was also applied. Two types of strength test were used: the compressive strength tests (DIN EN 196-1) for epoxy adhesive samples and the shear strength tests (DIN EN 1465) for adhesive joints. Both the analysis of the strength results of the samples of epoxy adhesive and adhesive joints as well as the failure analysis was carried out. On the basis of the results of strength tests it can be stated that the greatest deformation occurred for the samples of epoxy adhesive containing the modified epoxy resin (epoxy number—0.40) and the polyamide curing agent, and the smallest for the samples of epoxy adhesive containing the basic epoxy resin (epoxy number—0.49–0.52) and the polyamide curing agent. The epoxy adhesives with a smaller amount of curing agent were characterized by higher strength. This applies to all analyzed epoxy resins. The same dependences were obtained for the strength of adhesive joints of steel sheets made of the analyzed epoxy adhesive.


Author(s):  
Davood Askari ◽  
Mehrdad N. Ghasemi-Nejhad

Owing to their superior mechanical properties, carbon nanotubes (CNTs) can be used as an additional reinforcement to improve the mechanical properties of laminated composite materials. To incorporate the excellent properties of CNTs into the existing traditional composite technology, vertically aligned high density arrays of CNTs were grown perpendicular to the surface of 2-D woven cloths and tows of various fibrous materials. The nano-forest like structures of fabrics is used to fabricate 3-D reinforced nanocomposites. Due to the presence of aligned CNTs in through-the-thickness direction, it is expected that the inter-laminar and through-the-thickness properties of the composite laminate will be improved considerably. To demonstrate the effectiveness of our approach, various composite single lap-joint specimens were fabricated for inter-laminar shear strength testing. Carbon woven cloths with and without CNTs nano-forests were inserted in between the single lap-joints using epoxy adhesive to measure the interlaminar shear strength improvements due to the presence of through-the-thickness aligned CNTs nano-forests. It is observed that single lap-joints with carbon cloth insertion layers having CNTs nano-forest can carry up to 12% higher shear stress and 16% higher strain-to-failure. The failures of samples with nano-forests were completely cohesive while the sample with carbon woven cloth insertion failed adhesively. This concludes that the adhesion of adjacent carbon fabric layers can be considerably improved due to the growth of vertically aligned CNTs nano-forest in through-the-thickness direction.


2020 ◽  
Vol 91 (12) ◽  
pp. 7-15 ◽  
Author(s):  
Omid Sam-Daliri ◽  
Mohammadreza Farahani ◽  
Alireza Araei

Carbon nanotubes (CNT) are ideally suited to be employed for damage sensing in fiber rein- forced composite structures. In this work, the capability of CNTs for crack extension of a single lap Al-Al adhesive joints (SLJ) under shear load is studied using electrical resistance change. Different weight per- cent of CNT are added to epoxy adhesive. Epoxy adhesive with high concentration of CNT is obtained during shear loading to have the maximum strength and provide the best sensory properties. To provide a more concise evaluation of the crack extension in the adhesive layer under shear load, artificial defects are embedded into the SLJ specimens. The effects of square and circular defects with two different sizes on the crack extension in the adhesive layer are evaluated. The results showed that the maximum relative resistance change has occurred by 220% when the microcracks are initiated and accordingly developed from the nanoadhesive and changed its direction from the Square defect boundary. Additionally, in comparison with interface fracture in defective adhesive joint, when a part of crack grows through the adhesive layer, the resistance change showed higher values.


2014 ◽  
Vol 797 ◽  
pp. 169-174
Author(s):  
José M. Arenas Reina ◽  
Rosa Ocaña López ◽  
Cristina Alía García ◽  
Julián J. Narbón Prieto

This work analyzes the degradation of aluminum-composite adhesive joints under the action of water and motor oil. For this purpose, we have performed an accelerated ageing of the adhesive joint by immersion in water and oil. Likewise, we have evaluated the loss of mechanical properties that aging causes into adhesive joint. First, tests have been performed with bulk adhesive specimens (epoxy and polyurethane) immersed in water and motor oil during independent periods of time (1 at 128 days) in order to study the diffusion of water and motor oil into the adhesive. Second, we have evaluated the loss of mechanical properties that aging causes in the adhesive joint. Tests conclusions show that water degrades the adhesive more than motor oil. Additionally and under the action of water and motor oil, polyurethane adhesive joints retain their mechanical properties better than epoxy adhesive joints.


2015 ◽  
Vol 53 (8) ◽  
pp. 535-540 ◽  
Author(s):  
Young Gun Ko ◽  
Dong Hyuk Shin ◽  
Hae Woong Yang ◽  
Yeon Sung Kim ◽  
Joo Hyun Park ◽  
...  

2012 ◽  
Vol 2 (6) ◽  
pp. 166-168 ◽  
Author(s):  
Dr.T.Ch.Madhavi Dr.T.Ch.Madhavi ◽  
◽  
Pavithra.P Pavithra.P ◽  
Sushmita Baban Singh Sushmita Baban Singh ◽  
S.B.Vamsi Raj S.B.Vamsi Raj ◽  
...  

2015 ◽  
Vol 10 (1) ◽  
pp. 2641-2648
Author(s):  
Rizk Mostafa Shalaby ◽  
Mohamed Munther ◽  
Abu-Bakr Al-Bidawi ◽  
Mustafa Kamal

The greatest advantage of Sn-Zn eutectic is its low melting point (198 oC) which is close to the melting point. of Sn-Pb eutectic solder (183 oC), as well as its low price per mass unit compared with Sn-Ag and Sn-Ag-Cu solders. In this paper, the effect of 0.0, 1.0, 2.0, 3.0, 4.0, and 5.0 wt. % Al as ternary additions on melting temperature, microstructure, microhardness and mechanical properties of the Sn-9Zn lead-free solders were investigated. It is shown that the alloying additions of Al at 4 wt. % to the Sn-Zn binary system lead to lower of the melting point to 195.72 ˚C.  From x-ray diffraction analysis, an aluminium phase, designated α-Al is detected for 4 and 5 wt. % Al compositions. The formation of an aluminium phase causes a pronounced increase in the electrical resistivity and microhardness. The ternary Sn-9Zn-2 wt.%Al exhibits micro hardness superior to Sn-9Zn binary alloy. The better Vickers hardness and melting points of the ternary alloy is attributed to solid solution effect, grain size refinement and precipitation of Al and Zn in the Sn matrix.  The Sn-9%Zn-4%Al alloy is a lead-free solder designed for possible drop-in replacement of Pb-Sn solders.  


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