scholarly journals Adhesive Bonding of Copper Prepared by Laser-Interference near the Interference Structuring Limits

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3485
Author(s):  
Haotian Liu ◽  
Justin A. Weibel ◽  
Eckhard A. Groll ◽  
Adrian S. Sabau ◽  
Patrick Geoghegan ◽  
...  

Adhesive bonding requires adequate surface preparation for ensuring an appropriate joint quality. The interest in adhesive joining has recently expanded to thermal systems having a large number of joints employed for manufacturing and assembly. This study presents surface topology of copper 110 produced by a laser-interference setup that would theoretically yield a periodicity of 1.7 μm, which is near the 1.6–2 μm structuring limit that was estimated based on thermal diffusion length scale for an 8 ns laser pulse. The results show that although the expected periodic interference structuring was not attained, the melt-induced texturing was affected by the laser-interference profile. Single-lap shear tests were performed with specimen surfaces prepared by traditional abrasion and laser-interference structuring methods. Several laser processing parameters, such as the laser spot size, density, number of pulses, and raster speed, were studied. Scanning electron microscope and profilometry measurements were used to characterize the processed surface microstructures. Web-like structures, which indicate widespread melting, were shown to be formed at different processing conditions. Based on the surface topologies investigated, two laser raster speeds were selected to make single-lap-joint specimens. Baseline joints were prepared by abrading joining specimens. The shear-lap strength and displacement at maximum load were shown to be higher by 16.8% and 43.8% for the laser-structured specimens than those of the baseline specimens, respectively. Moreover, the load-displacement curves indicated that the laser-structured joints were more ductile than those without laser-structuring. The increased ductility for the laser-structured joints was found to yield an increase in the energy absorbed during shear-lap testing of approximately of 80–90% over those measured for baseline joints. It is another indicator that laser-interference structuring enhanced the bonding performance of single-lap shear joints.

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Chiara Mandolfino ◽  
Enrico Lertora ◽  
Carla Gambaro

The purpose of the paper is to investigate the effects of low pressure plasma treatment on wettability of carbon fibre reinforced polymer samples and on shear properties of adhesive bonded joints based on these substrates. In particular, two plasma process parameters, exposure time and power input, were optimized, performing contact angle evaluation on lap-shear tests. The plasma treatment was also compared with a conventional mechanical abrasion and untreated and only degreased specimens. The experimental results show that choosing the optimal parameters is possible to improve the wettability of composite substrates and reduce the contact angle.


Author(s):  
S. L. Ngoh ◽  
S. C. Tan ◽  
C. S. Goh ◽  
J. Wei

Adhesive bonding offers many advantages, such as light weight, ease of manufacturing, corrosion resistance and more uniform stress distribution at joint. In order to achieve good initial adhesion and durability of adhesive bonded aluminum joint, pre-treatment of the aluminum substrate is essential. Some of the surface pre-treatment procedures commonly used are chromium-based chemical and electro-chemical methods. However, due to the environmental and health concerns, and legislation to ban the use of hexavalent chromium, there is a need to omit the use of chromium-based pre-treatment methods in the surface preparation process. Therefore, this work aims to study the effect of the developed hybrid chromium-free surface pre-treatment method on the bonding strength of adhesive bonded aluminum joint. The study on the effects of solution concentration level and processing time of the hybrid treatment on the bonding strength suggests that bonding strength can be improved through enhancement of mechanical interlocking and increase of bonding area between the adhesive and adherend. Even though comparable or rougher surface morphologies were obtained from hybrid treatments as compared to the chromium-based treatment, lower bonding strengths were observed. This further suggests that the nano-scale level interaction between the adhesive and adherend has vital effect on the bonding performance.


Author(s):  
D. Voswinkel ◽  
D. Kloidt ◽  
O. Grydin ◽  
M. Schaper

AbstractLaser surface treatment of metals is one option to improve their properties for adhesive bonding. In this paper, a pulsed YVO4 Laser source with a wavelength of 1064 nm and a maximum power of 25 W was utilized to increase the surface area of the steel HCT490X in order to improve its bonding properties with a carbon fibre reinforced polymer (CFRP). Investigated was the influence of the scanning speed of the laser source on the bonding properties. For this purpose, the steel surfaces were ablated at a scanning speed between 1500 and 4500 mm/s. Afterwards the components were bonded with the adhesive HexBond™ 677. After lap shear tests were carried out on the specimen, the surfaces were inspected using scanning electron microscopy (SEM). The experiments revealed that the bonding quality can be improved with a high scanning speed, even when the surface is not completely ablated.


2021 ◽  
Author(s):  
Antonello Astarita ◽  
Fausto Tucci ◽  
Alessia Teresa Silvestri ◽  
Michele Perrella ◽  
Luca Boccarusso ◽  
...  

Abstract This paper deals with the dissimilar friction stir lap welding of AA2198 and AA7075 sheets. The influence of processing parameters, namely welding speed and tool rotational speed on joint features, microstructure, and mechanical properties were investigated implementing a full factorial design of experiments. During the welding process, axial and transversal forces were continuously measured using a dedicated sensed fixture aiming at the correlation of this processing parameter with the quality of the achieved joints. The reported outcomes showed a very narrow processing window in which it was possible to avoid the formation of defects while the formation of an hook was observed for all the joints welded. The influence of the weld bead morphology on the lap shear strength was elucidated proving that the strength is ruled by the hook morphology. A correlation between the process parameters and the forces arising was also attempted. The final microstructure of the joints was studied and explained and also compared with the microhardness results.


Author(s):  
Zhe Gao ◽  
Haris Khan ◽  
Jingjing Li ◽  
Weihong Guo

Abstract This research focused on developing a hybrid quality monitoring model through combining the data driven and key engineering parameters to predict the friction stir blind riveting (FSBR) joint quality. The hybrid model was formulated through utilizing the in-situ processing and joint property data. The in-situ data involved sensor fusion (force and torque signals) and key processing parameters (spindle speed, feed rate and stacking sequence) for data-driven modeling. The quality of the FSBR joints was defined by the tensile strength. Further, the joint cross-sectional analysis and failure modes in lap-shear tests were employed to confirm the efficacy of the proposed model and development of the process-structure-property relationship.


2006 ◽  
Vol 911 ◽  
Author(s):  
Joseph John Sumakeris ◽  
Brett A. Hull ◽  
Michael J. O'Loughlin ◽  
S. Ha ◽  
Marek Skowronski ◽  
...  

AbstractWe describe surface preparation and epilayer growth techniques that readily reduce the density of Vf drift inducing basal plane dislocations in epilayers to less than 10 cm-2 and permit the fabrication of bipolar SiC devices with very good Vf stability. The optimal process route requires etching the substrate surface prior to epilayer growth to enhance the natural conversion of basal plane dislocations into threading edge dislocations during epilayer growth. The surface of this relatively rough “conversion” epilayer is subsequently repolished prior to growing the device structure. We provide details on processing parameters and potential problems as well as describe devices produced using this low basal plane dislocation growth processes.


RSC Advances ◽  
2020 ◽  
Vol 10 (51) ◽  
pp. 30289-30296 ◽  
Author(s):  
Chia-Wen Tsao ◽  
Wan-Ci Syu

We investigated dry adhesive bonding of thermoplastic microfluidics. The bonding performance is correlated to the air bubble encapsulation and Saffman–Taylor finger formation phenomena at the interface.


2019 ◽  
Vol 26 (3) ◽  
pp. 557-565 ◽  
Author(s):  
Travis Edward Shelton ◽  
Dylan Joseph Stelzer ◽  
Carl R. Hartsfield ◽  
Gregory Richard Cobb ◽  
Ryan P. O'Hara ◽  
...  

Purpose For many applications, including space applications, the usability and performance of a component is dependent on the surface topology of the additively manufactured part. The purpose of this paper is to present an investigation into minimizing the residual surface roughness of direct metal laser sintering (DMLS) samples by manipulating the input process parameters. Design/methodology/approach First, the ability to manipulate surface roughness by modifying processing parameters was explored. Next, the surface topography was characterized to quantify roughness. Finally, microthruster nozzles were created both additively and conventionally for flow testing and comparison. Findings Surface roughness of DMLS samples was found to be highly dependent on the laser power and scan speed. Because of unintended partially sintered particles adhering to the surface, a localized laser fluence mechanism was explored. Experimental results show that surface roughness is influenced by the varied parameters but is not a completely fluence driven process; therefore, a relationship between laser fluence and surface roughness can be incorporated but not completely assumed. Originality/value This paper serves as an aid in understanding the importance of surface roughness and the mechanisms associated with DMLS. Rather than exploring a more common global energy density, a localized laser fluence was initiated. Moreover, the methodology and conclusions can be used when optimizing parts via metal additive manufacturing.


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