scholarly journals Microstructure and mechanical performance of dissimilar metal joints of aluminium alloy and stainless steel by cutting-assisted welding-brazing

2021 ◽  
Author(s):  
Huibin Xu ◽  
Wei Cong ◽  
Donghua Yang ◽  
Yanlong Ma ◽  
Wanliang Zhong ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Aluminium Alloy ◽  
Cutting Tool ◽  
Mechanical Performance ◽  
Interfacial Structure ◽  
304 Stainless Steel ◽  
Small Scale ◽  
Joint Interface ◽  
Micro Scale ◽  
Macro Scale

Abstract The 5052 aluminium alloy and 304 stainless steel were successfully joined by cutting-assisted welding-brazing (CAWB) method without using flux. Dual-scale interfacial structures were achieved by manipulating the cutting tool profile. Results indicated that the macro-scale interfacial structure was produced at the joint interface when the taper step-shape cutting tool was adopted. As the cutting tool step was increased to 6-step, the micro-scale interface took on serrated morphology and a layer of continuous and wavy intermetallic compound (IMC) with an average thickness of 3.3 μm was formed at the interface. The τ 4 IMC particles and the FeAl 6 phases on a small scale were dispersed homogeneously in the welded seam. The maximum tensile strength of the joints reached 152.3 MPa upon tensile loading, 75% that of the 5052 aluminium base metal. The strong and reliable Al/steel dissimilar joints were attributed to the particle reinforced weld metal and the macro- and micro-scale dual self-locking structure at the interface.

Numerical Modeling of Transport Phenomena and Dendritic Growth in Laser Conduction Welding of 304 Stainless Steel

2011 ◽  
Author(s):  
Wenda Tan ◽  
Neil S. Bailey ◽  
Yung C. Shin
Keyword(s):  
Stainless Steel ◽  
Molten Pool ◽  
Dendritic Growth ◽  
Quantitative Agreement ◽  
304 Stainless Steel ◽  
Experimental Result ◽  
Scale Model ◽  
Transient Model ◽  
Micro Scale ◽  
Macro Scale

A multi-scale model is developed to investigate the heat/mass transport and dendrite growth in laser spot conduction welding. A macro-scale transient model of heat transport and fluid flow is built to study the evolution of temperature and velocity field of the molten pool. The molten pool geometry and other solidification parameters are calculated, and the predicted pool geometry matches well with experimental result. On the micro-scale level, the dendritic growth of 304 stainless steel is simulated by a novel model that has coupled the Cellular Automata (CA) and Phase Field (PF) methods. The epitaxial growth is accurately identified by defining both the grain density and dendrite arm density at the fusion line. By applying the macro-scale thermal history onto the micro-scale calculation domain, the microstructure evolution of the entire molten pool is simulated. The predicted microstructure achieves a good quantitative agreement with the experimental results.

Weldability and Joining Characteristics of AISI D2/AISI 304 Steels Using Semisolid Diffusion Joining

2019 ◽  
Vol 285 ◽  
pp. 115-120
Author(s):  
Mohammed N. Abdul Razaq ◽  
M. Zaidi Omar ◽  
Salah Al-Zubaidi ◽  
Khaled S. Alhawari ◽  
Mnel A. Abdelgnei
Keyword(s):  
Stainless Steel ◽  
Smooth Transition ◽  
304 Stainless Steel ◽  
Joint Interface ◽  
Aisi 304 ◽  
Thermal Expansion Coefficients ◽  
New Process ◽  
Aisi D2 ◽  
Semi Solid ◽  
Aisi D2 Tool Steel

The application of hybrid structures or components made of dissimilar metal offers the potential to utilize the advantages of different materials often providing unique solutions to engineering requirements. However, the joining of materials by conventional welding techniques becomes difficult if the physical properties such as melting temperature and thermal expansion coefficients of the two materials are different. In this study, a new process of joining semi-solid AISI D2 tool steel and AISI 304 stainless steel using a partial remelting method is proposed. Moreover, the effect of the holding time on the microstructural evolution was investigated. The processing temperatures for the thixojoining was 1320°C and held for 5, 12, 20 and 30 minutes, respectively. The results obtained from investigating the basic geometries demonstrated a good joining quality that differs from the conventional process of welding. Metallographic analyses along the joint interface between semi-solid AISI D2 and 304 stainless steel showed a smooth transition from one to the other, with neither oxides nor microcracking being observed.

A Micro-Scale Swimmer Propelled by Traveling Surface Waves

2011 ◽  
Author(s):  
Izhak Bucher ◽  
Eyal Setter
Keyword(s):  
Travelling Wave ◽  
Superior Performance ◽  
Small Scale ◽  
Micro Scale ◽  
Viscous Forces ◽  
Macro Scale ◽  
Robotic Devices ◽  
Compact Design ◽  
Micro Organisms ◽  
Efficient Power

Micro-scale slender swimmers are frequently encountered in nature and recently in micro-robotic applications. The swimming mechanism examined in this article is based on small transverse axi-symmetrical travelling wave deformations of a cylindrical long shell. In very small scale, inertia forces become negligible and viscous forces dominate most propulsion mechanisms being used by micro-organisms and robotic devices. The present paper proposes a compact design principle that provides efficient power to propel and maneuver a micro-scale device. Shown in this paper is a numerical analysis which couples the MEMS structure to the surrounding fluid. Analytical results compare the proposed mechanism to commonly found tail (flagella) driven devices, and a parametric comparison is shown suggesting it has superior performance. Numerical studies are preformed to verify the analytical model. Finally, a macro-scale demonstrator swimming in an environment with similar Reynolds numbers to the ones found in small scale is shown and its behavior in the laboratory is compared to the theory.

Characterization of Al2O3–304 stainless steel braze joint interface

2007 ◽  
Vol 61 (14-15) ◽  
pp. 2982-2985 ◽  
Author(s):  
Abhijit Kar ◽  
Ajoy Kumar Ray
Keyword(s):  
Stainless Steel ◽  
304 Stainless Steel ◽  
Joint Interface ◽  
Braze Joint

Finite Elements Modeling of Mechanical and Acoustic Properties of a Ceramic Metamaterial Assembled by Robocasting

2016 ◽  
Vol 821 ◽  
pp. 364-371 ◽  
Author(s):  
Alena Kruisová ◽  
Hanuš Seiner ◽  
Petr Sedlák ◽  
Michal Landa ◽  
Benito Román-Manso ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Acoustic Properties ◽  
Stress Concentrations ◽  
Micro Scale ◽  
Contact Points ◽  
Finite Elements Modeling ◽  
Macro Scale ◽  
Anisotropic Elastic

Finite element modeling (FEM) was used for numerical simulations of mechanical performance of aperiodic silicon-carbide scaffold manufactured by robocasting. The FEM approach enabled reliable calculation of theeffective anisotropic elastic properties of the scaffold at the macro-scale, as well as of the acoustic band structureindicating the metamaterial-like behavior of the material at the micro-scale. In addition, the micromechanics of thescaffold was discussed based on the outputs of the model: the mechanisms of the extremely soft shearing modes wereidentified and the corresponding stress concentrations arising at the contact points in the scaffold were analyzedwith respect to the possible failure modes of the robocast structure.

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