scholarly journals Effects of static load and residual stress on fused silica direct bonding interface properties

2021 ◽  
Vol 127 (12) ◽  
Author(s):  
Pascal Birckigt ◽  
Kevin Grabowski ◽  
Gilbert Leibeling ◽  
Thomas Flügel-Paul ◽  
Martin Heusinger ◽  
...  
Keyword(s):  
Residual Stress ◽  
Bonding Strength ◽  
Smooth Surface ◽  
Static Load ◽  
Fused Silica ◽  
Interface Stress ◽  
Bonding Interface ◽  
Interface Properties ◽  
Large Area ◽  
Annealing Step

AbstractDefect free direct bonding of rigid and large area glass samples, such as prisms, becomes increasingly important for the manufacturing of modern optical and optomechanical components. Typically, in order to apply a static load during the annealing step, specialized heat-resistant pressure mountings are required. This makes manufacturing effortful and cost-intensive. In this paper, we present plasma activated bonding experiments conducted on fused silica plates where residual stress has been introduced prior to the contacting step and where annealing is performed with and without a static load. We find that in case of a sufficiently smooth surface, bonding strength is insensitive towards residual stress or static load, or more precisely, towards the interface stress. Furthermore, the residual Fresnel reflection losses of the realized bonding interface were optically measured and they amount to only $$10^{-6}$$ 10 - 6 . We propose that a consideration of the change in Gibbs free energy, dG, allows qualitatively predicting the resulting bonding strength and its spatial distribution, where dG is determined by surface energy and interface stress. At the end of this article, conceivable applications are discussed.

scholarly journals Shearing Characteristics of Cu-Cu Joints Fabricated by Two-Step Process Using Highly -Oriented Nanotwinned Cu

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1864
Author(s):  
Jia-Juen Ong ◽  
Dinh-Phuc Tran ◽  
Shih-Chi Yang ◽  
Kai-Cheng Shie ◽  
Chih Chen
Keyword(s):  
Electrical Resistance ◽  
Bonding Strength ◽  
Annealing Process ◽  
Bonding Interface ◽  
Post Annealing ◽  
Ductile Fractures ◽  
Annealing Step ◽  
Scaling Down ◽  
Cu Bonding ◽  
Micrometer Scale

Cu-Cu bonding has the potential to break through the extreme boundary of scaling down chips’ I/Os into the sub-micrometer scale. In this study, we investigated the effect of 2-step bonding on the shear strength and electrical resistance of Cu-Cu microbumps using highly <111>-oriented nanotwinned Cu (nt-Cu). Alignment and bonding were achieved at 10 s in the first step, and a post-annealing process was further conducted to enhance its bonding strength. Results show that bonding strength was enhanced by 2–3 times after a post-annealing step. We found 50% of ductile fractures among 4548 post-annealed microbumps in one chip, while the rate was less than 20% for the as-bonded counterparts. During the post-annealing, interfacial grain growth and recrystallization occurred, and the bonding interface was eliminated. Ductile fracture in the form of zig-zag grain boundary was found at the original bonding interface, thus resulting in an increase in bonding strength of the microbumps.

scholarly journals The Interfacial Characterization and Performance of Cu/Al-Conductive Heads Processed by Explosion Welding, Cold Pressure Welding, and Solid-Liquid Casting

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 237 ◽  
Author(s):  
Yanni Wei ◽  
Hui Li ◽  
Fu Sun ◽  
Juntao Zou
Keyword(s):  
Corrosion Resistance ◽  
Bonding Strength ◽  
Explosive Welding ◽  
Slag Inclusion ◽  
Explosion Welding ◽  
Bonding Interface ◽  
Pressure Welding ◽  
And Performance ◽  
Solid Liquid ◽  
Cold Pressure

The Cu/Al composites conductive head is widely used in hydrometallurgy as the core component of cathode plate. Its conductive properties directly affect the power consumption, and the bonding strength and corrosion resistance determine the conductive head service life. The Cu/Al conductive head prepared by explosion welding, cold pressure welding, and solid-liquid casting methods were investigated in this paper. The interface microstructure and compositions were examined by scanning electron microscope and X-ray energy dispersive spectrometry. The bonding strength, interface conductivity, and the corrosion resistance of three types of joints were characterized. The Cu/Al bonding interface produced by explosive welding presented a wavy-like morphology with typical defects and many of brittle compounds. A micro-interlocking effect was caused by the sawtooth structures on the cold pressure welding interface, and there was no typical metallurgical reaction on the interface. The Cu/Al bonding interface prepared by solid-liquid casting consisted mainly of an Al-Cu eutectic microstructure (Al2Cu+Al) and partial white slag inclusion. The thickness of the interface transition layer was about 200–250 µm, with defects such as holes, cracks, and unwelded areas. The conductivity, interfacial bonding strength, and corrosion resistance of the conductive head prepared by explosive welding were superior to the other two.

CFD modelling of a novel hydrodynamic suspension polishing process for ultra-smooth surface with low residual stress

2017 ◽  
Vol 317 ◽  
pp. 320-328 ◽  
Author(s):  
Huan Qi ◽  
Zhong Xie ◽  
Tao Hong ◽  
Yang-yu Wang ◽  
Fan-zhi Kong ◽  
...  
Keyword(s):  
Residual Stress ◽  
Smooth Surface ◽  
Polishing Process ◽  
Cfd Modelling

Coupled Thermal-Mechanical Analysis of CO2 Laser Irradiation on Fused Silica

2016 ◽  
Vol 1136 ◽  
pp. 531-536
Author(s):  
Run Qiang Li ◽  
Peng Yao ◽  
Hao Meng ◽  
Jun Wang ◽  
Ke Zhang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Laser Irradiation ◽  
Laser Energy ◽  
Viscoelastic Behavior ◽  
Mechanical Analysis ◽  
Fused Silica ◽  
Depth Of Cut ◽  
Residual Tensile Stress ◽  
Thermally Induced

To grind fused silica in ductile mode, it was proposed to repair surface and subsurface micro cracks of fused silica by CO2 laser irradiation. However, excessive residual stress remains on the surface because the melt fused silica on the surface quenches in air. It causes the critical depth of cut for ductile grinding fused silica to be smaller than 0.2μm. To investigate the distribution of the residual stress and look for an optimal manner of irradiation to control residual tensile stress, a numerical model of was built for simulating the dynamic behavior of fused silica when irradiated by CO2 laser. Laser energy absorption, heat transmission, viscoelastic behavior of fused silica and thermally induced stress were considered in the numerical simulation. The results show how the residual stress is formed and distributed. We found that an appropriate control of the temperature field as a function of time and position in the laser process is the key to reduce the residual stress. Therefore, three kinds of processes were proposed to reduce residual tensile stress on the surface of fused silica introduced by laser irradiation. The residual stress distributions of these three processes were compared by numerical analysis to decide a better method of laser irradiation.

Mesoscopic damage evolution on bonding interface and its influence on macroscopic performance deterioration of reinforced concrete member

2019 ◽  
Vol 08 (02) ◽  
pp. 1950005
Author(s):  
Ying Wang ◽  
Yuqian Zheng ◽  
Xuan Wang
Keyword(s):  
Reinforced Concrete ◽  
Bonding Strength ◽  
Element Model ◽  
Bonding Interface ◽  
Interfacial Damage ◽  
Concrete Member ◽  
Steel Bar ◽  
Reinforced Concrete Member ◽  
Bonding Property ◽  
Performance Deterioration

Slip or debonding of bonding interface is the key cause of the performance degradation or failure of the reinforced concrete (RC) member. In this paper, based on Monte Carlo method, a mesoscopic finite element model composed of mortar, coarse aggregate and steel rebar was established to consider the mesoscopic damage on the bonding interface and its influence on macroscopic performance deterioration of RC specimen. The results show that the simulation results fit well with experimental data. Higher initial interfacial damage results in lower bonding strength and smaller final displacement. Higher mortar modulus could greatly improve the initial bonding property and bonding strength, but slightly increase the final damage. Compared with the RC specimen model with plain steel bar, the model with deformed steel bar shows a longer duration of nonlinear increase for drawing force and lower bonding strength. When confinement is applied, the coalescence of damage zones is prevented due to the effect of thread. Therefore, the application of confinement could increase the bonding strength and the initial bonding property.

Dependence of bonding strength and variations in residual stress on interface wedge angles and bonding temperature conditions

MRS Advances ◽  
2020 ◽  
Vol 5 (33-34) ◽  
pp. 1765-1774
Author(s):  
Shunsuke Muraoka ◽  
Masayoshi Tateno
Keyword(s):  
Residual Stress ◽  
Bonding Strength ◽  
Bonding Temperature ◽  
Wedge Angle ◽  
Fracture Pattern ◽  
Experimental Results ◽  
Joint System ◽  
Stress Variation ◽  
Temperature Conditions ◽  
Interface Edge

AbstractResidual stress can considerably weaken systems with ceramics-to-metal joints. Herein, we investigate the dependence of bonding strength and residual stress variation of a ceramics-to-metal joint system on the interface wedge angle and bonding temperature condition. First, disparity between large-scale displacement models with varying work-hardening parameters was confirmed using thermal elastoplastic Finite Element Method (FEM) analysis. Each interface wedge shape was set to a plane surface to compare FEM results to experimental results related to the effect of the interface wedge angle on the practical bonding strength. The experimental results were specifically for a system consisting of Si3N4-WC/TiC/TaC bonded to Ni plate. The effects of the wedge angle of the metal side on residual stress near the interface edge were numerically predicted using FEM models. The interface wedge angles for this model, φ1 and φ2, were defined using the configuration angle between the interface and free surfaces of both materials. The numerical results showed that the stress σr on the free surface of the ceramic side was concentrated near the interface edge at which discontinuity in the stress state is generated. Dependence of the residual stress variation on both the wedge angle and temperature conditions can be predicted. It was confirmed that the bonding strength improves with decreasing residual stress in geometrical conditions. Therefore, residual stress appears to be a predominant factor affecting bonding strength. The observed fracture pattern showed that the fracture originated near the interface edges, after which small cracks propagated on the ceramic side. The residual stress is presumed to dominate bonding strength as the fracture occurred near the interface edge of the ceramic side. Results showed that the maximum bonding strength appears at the geometrical condition where the fracture pattern changes to φ2 lower than 90° of joint bonded at 980 °C. Therefore, the optimum interface wedge angle depends on a combination of materials and bonding temperature conditions, because the weak point of the bonded joint system will affect the stiffness balance of both materials and the adhesion power of the bonded interface.

scholarly journals Stress Gradient Analysis by Noncomplanar x-Ray Diffraction and Corresponding Refraction Correction

2014 ◽  
Vol 996 ◽  
pp. 162-168 ◽  
Author(s):  
Andrei Benediktovitch ◽  
Tatjana Ulyanenkova ◽  
Jozef Keckes ◽  
Alex Ulyanenkov
Keyword(s):  
Residual Stress ◽  
Gradient Analysis ◽  
Stress Gradient ◽  
X Ray Diffraction ◽  
Large Area ◽  
Present Contribution ◽  
Nondestructive Technique ◽  
X Ray ◽  
Tin Coatings ◽  
Measurement Geometry

X-ray residual stress analysis is a widespread nondestructive technique to investigate the residual stress and residual stress gradient in thin films and protective coatings.In the present contribution we introduce a new method based on the noncomplanar measurement geometry that allow to span large area of sin2ψ and penetration depth values without sample inclination. The refraction correction and absorption is considered in details for the noncomplanar measurements. The proposed technique is applied to determine stress gradients of blasted hard TiN coatings.

Experimental Study on Residual Stresses of Al2O3 Coating by Laser Re-Melting

2010 ◽  
Vol 431-432 ◽  
pp. 446-449
Author(s):  
De Jun Kong ◽  
Kai Yu Luo ◽  
Hong Miao
Keyword(s):  
Residual Stress ◽  
Experimental Study ◽  
Tensile Stress ◽  
Residual Stresses ◽  
High Power ◽  
Bonding Strength ◽  
Strengthening Mechanism ◽  
Al2o3 Coating ◽  
Micro Hardness ◽  
Continuous Co2 Laser

The surface of Al2O3 coating sprayed on 40Cr substrate was re-melted with high power continuous CO2 laser, and its micro-hardness and residual stresses were measured, respectively. The strengthening mechanism of Al2O3 coating by laser re-melting was analyzed and discussed. The experimental results shown that the surface of Al2O3 coating by laser re-melting is neat and smooth, and its compositions are even, its structures are compact, and Al2O3 coating is evenly distributed in its surface with grain forms, and its micro-hardness increases about 200%; Residual stress of Al2O3 coating by laser re-melting is changed into compressive stress from tensile stress, which is benefit to improving bonding strength of coating-substrate interface.

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