scholarly journals Bonding of Al6061 by Hot Compression Forming: A Computational and Experimental Study of Interface Conditions at Bonded Surfaces

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3598
Author(s):  
Brigit Mittelman ◽  
Michael Ben-Haroush ◽  
Ira Aloush ◽  
Linoy Mordechay ◽  
Elad Priel
Keyword(s):  
Bonding Strength ◽  
Effective Properties ◽  
Hot Compression ◽  
Finite Element Models ◽  
Temperature Dependent ◽  
Bonding Quality ◽  
Field Patterns ◽  
Metallurgical Bonding ◽  
Interface Contact ◽  
Experimental Findings

In recent years, there has been a growing interest in composite components, which may be designed to provide enhanced mechanical and physical effective properties. One of the methods available to produce such components is joining by plastic deformation, which results in metallurgical bonding at the interface. However, the portions of the interface that are bonded and the inhomogeneity in the bonding strength achieved at the interface tend to be overlooked. In the present study, Al6061 beams were bonded, by hot compression (300–500 °C) to different degrees of reduction. The compression was followed by tensile debonding experiments and the revealed interface was microscopically characterized in order to determine the areas that were metallurgically bonded. The SEM characterization revealed that the actual bonded area is much smaller than the interface contact area. Thermo-mechanical finite element models of the compression stage were used to investigate the thermo-mechanical fields, which develop along the interface and influence the resulting bonding strength. The principal strain field patterns across the interface area were shown to be similar to the experimentally observed temperature-dependent bonding patterns. In addition, a quantitative criterion for bonding quality was implemented and shown to correlate with the experimental findings.

Numerical Investigation on Weld-Induced Imperfections in Aluminum Ship Plates

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Bai-Qiao Chen ◽  
C. Guedes Soares
Keyword(s):  
Finite Element ◽  
Aluminum Alloy ◽  
Material Properties ◽  
Welding Process ◽  
Finite Element Models ◽  
Finite Element Analyses ◽  
Temperature Dependent ◽  
Military Applications ◽  
Structural Responses ◽  
Or In Military

The present work aims at better understanding and predicting the thermal and structural responses of aluminum components subjected to welding, contributing to the design and fabrication of aluminum ships such as catamarans, lifesaving boats, tourist ships, and fast ships used in transportation or in military applications. Taken into consideration the moving heat source in metal inert gas (MIG) welding, finite element models of plates made of aluminum alloy are established and validated against published experimental results. Considering the temperature-dependent thermal and mechanical properties of the aluminum alloy, thermo-elasto-plastic finite element analyses are performed to determine the size of the heat-affected zone (HAZ), the temperature histories, the distortions, and the distributions of residual stresses induced by the welding process. The effects of the material properties on the finite element analyses are discussed, and a simplified model is proposed to represent the material properties based on their values at room temperature.

Designing Optimal Volume Fractions For Functionally Graded Materials With Temperature-Dependent Material Properties

2006 ◽  
Vol 74 (5) ◽  
pp. 861-874 ◽  
Author(s):  
Florin Bobaru
Keyword(s):  
Functionally Graded Materials ◽  
Material Properties ◽  
Volume Fraction ◽  
Effective Properties ◽  
Functionally Graded ◽  
Dominant Factor ◽  
Temperature Dependent ◽  
Graded Materials ◽  
Critical Stresses ◽  
Non Linear

We present a numerical approach for material optimization of metal-ceramic functionally graded materials (FGMs) with temperature-dependent material properties. We solve the non-linear heterogeneous thermoelasticity equations in 2D under plane strain conditions and consider examples in which the material composition varies along the radial direction of a hollow cylinder under thermomechanical loading. A space of shape-preserving splines is used to search for the optimal volume fraction function which minimizes stresses or minimizes mass under stress constraints. The control points (design variables) that define the volume fraction spline function are independent of the grid used in the numerical solution of the thermoelastic problem. We introduce new temperature-dependent objective functions and constraints. The rule of mixture and the modified Mori-Tanaka with the fuzzy inference scheme are used to compute effective properties for the material mixtures. The different micromechanics models lead to optimal solutions that are similar qualitatively. To compute the temperature-dependent critical stresses for the mixture, we use, for lack of experimental data, the rule-of-mixture. When a scalar stress measure is minimized, we obtain optimal volume fraction functions that feature multiple graded regions alternating with non-graded layers, or even non-monotonic profiles. The dominant factor for the existence of such local minimizers is the non-linear dependence of the critical stresses of the ceramic component on temperature. These results show that, in certain cases, using power-law type functions to represent the material gradation in FGMs is too restrictive.

Effect of CU Foam and Ag-Coated Layer on the Microstructure and Mechanical Behavior of Nano-Ag Sintered Joint

2020 ◽  
Author(s):  
Yang Liu ◽  
Zhao Li ◽  
Min Zhou ◽  
Xianghua Zeng ◽  
Fenglian Sun
Keyword(s):  
Shear Strength ◽  
Mechanical Behavior ◽  
Bonding Strength ◽  
Experimental Results ◽  
Bonding Quality ◽  
Deformation Ratio ◽  
Coated Layer ◽  
Ag Paste ◽  
Sintered Ag ◽  
Cu Foam

Abstract Cu foam (Cu-F) and Ag-coated Cu-F were added into nano-Ag paste to obtain Cu-F@nano-Ag composite sintered joint. The microstructure, hardness, and shear behavior of the sintered joints were investigated. Experimental results indicated that the addition of Cu-F and Ag-coated Cu-F suppressed the generation and propagation of cracks at the interface of the sintered joint. As the thickness of the Cu-F increased from 0.1mm to 0.2mm, the deformation ratio of the Cu-F sheet raised from 12 % to 50 %. Thereby, the hardness and bonding strength of the sintered joint was improved due to the microstructural densification. The bonding quality between Cu-F and sintered Ag is enhanced by the Ag-coating treatment. Therefore, the Ag-coated composite joints show higher shear strength than the others.

Accuracy Enhancement of Thermoelectric Simulation by Modeling the Electrical Contact

2016 ◽  
Vol 8 (4) ◽  
Author(s):  
Min Chen ◽  
Junling Gao ◽  
Zhengdong Kang ◽  
Jianzhong Zhang
Keyword(s):  
Statistical Modeling ◽  
System Simulation ◽  
Electrical Contact ◽  
Numerical Implementation ◽  
Temperature Dependent ◽  
Accuracy Improvement ◽  
Thermoelectric Modules ◽  
Accuracy Enhancement ◽  
Interface Resistance ◽  
Experimental Findings

The main objective of this study is to numerically analyze the uncertainty of the electrical interface resistance in thermoelectric modules (TEMs) and its contribution to the error of practical device and system simulation. To improve the simulation, the numerical implementation of the interface resistance in TEMs of any size, especially its temperature-dependent characteristics, is critical in the thermoelectric modeling. Using the electrothermal analogy and the PSpice simulator as the simulation baseline, the proposed nonlinear and statistical modeling of the interface resistance is examined and supported through extensive comparisons between experimental findings and numerical results. Considerable accuracy improvement is obtained for a single TEM and a system consisting of a number of interconnected TEMs.

Long-Term Bonding Strength between Flue Gas Desulfurization Gypsum and Polymer Cement Mortar

2012 ◽  
Vol 446-449 ◽  
pp. 1348-1351
Author(s):  
Ru Mu ◽  
Ling Wang ◽  
Wen Ling Tian ◽  
Wei Cao
Keyword(s):  
Flue Gas ◽  
Bonding Strength ◽  
Cement Mortar ◽  
Construction Materials ◽  
Flue Gas Desulfurization ◽  
Bonding Quality ◽  
Bonding Performance

The uncertainty of long-term bonding strength of flue gas desulfurization building gypsum and cement based construction materials is the major issue impeding the application of flue gas desulfurization building gypsum in construction. A polymer cement mortar is suggested to get high bonding quality with flue gas desulfurization building gypsum. Long-term bonding observation has been carried out to verify the bonding performance of suggested polymer cement mortar with flue gas desulfurization gypsum. The results show that the bonding strength is up to 3.0MPa, and the bonding between them is durable.

Study on the Inner-Lined Layers Bonding Strength at Different Temperatures of the Ceramic-Lined Tubing Prepared by the Centrifugal-SHS Method

2021 ◽  
Vol 1026 ◽  
pp. 122-128
Author(s):  
Shou Ze Wang ◽  
Shi Cheng Wei ◽  
Yi Liang ◽  
Bin Shi Xu ◽  
Yong Li Yang ◽  
...  
Keyword(s):  
Bonding Strength ◽  
Shear Failure ◽  
Alloy Layer ◽  
Element Analysis ◽  
Bonding Force ◽  
Macroscopic Structure ◽  
Metallurgical Bonding ◽  
Different Temperatures ◽  
Centrifugal Shs ◽  
Mechanical Bonding

The inner-lined layers bonding strength of the ceramic-lined tubing was measured from 25°C to 600°C. The macroscopic structure and microscopic characteristics of the slippage surface of the ceramic-lined tubing were observed using optical microscopy and scanning electron microscopy. Combined with finite element analysis of the residual stress distribution at different temperatures, the shear failure model of the ceramic-lined tubing at different temperatures was given. The mechanical bonding force at the C-A (ceramic layer-alloy layer) interface is greater than the metallurgical bonding force at the A-T (alloy layer-base tubing) interface at low temperature, and the mechanical bonding force at the C-A interface is less than the metallurgical bonding force at the A-T interface at high temperature. The transition temperature is about 200 °C.

A Viscoplastic Constitutive Model for Polyurethane Foams

2006 ◽  
Author(s):  
Mike Neilsen ◽  
Wei-Yang Lu ◽  
Bill Olsson ◽  
Terry Hinnerichs
Keyword(s):  
Large Deformation ◽  
Mechanical Response ◽  
Polyurethane Foams ◽  
Plasticity Model ◽  
Load Path ◽  
Temperature Dependent ◽  
Rigid Polyurethane Foams ◽  
Foam Model ◽  
Series Of Experiments ◽  
Experimental Findings

A series of experiments was recently performed to characterize the mechanical response of several different rigid polyurethane foams to large deformation. In these experiments, the effects of load path, loading rate, and temperature were investigated. Results from these experiments indicated that rigid polyurethane foams exhibit significant volumetric and deviatoric plasticity when they are compressed. Based on these experiments, a foam plasticity model that captures volumetric and deviatoric plasticity was developed. This model has a yield surface that is an ellipsoid about the hydrostat. These polymeric foams were also found to be very strain-rate and temperature dependent. Thus, a new viscoplastic foam model was developed to describe the mechanical response of these foams to large deformation at a variety of temperatures and strain rates. This paper includes a description of recent experiments and experimental findings. Next, development of a foam plasticity model and a viscoplastic foam model is described. Finite element simulations with the new models are compared with experimental results to show behavior that can and cannot be captured with these models.

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