Microstructure and Mechanical Properties of Laser Welded Lap Joints of Ti-6Al-4V Alloy

2011 ◽  
Vol 311-313 ◽  
pp. 2375-2378 ◽  
Author(s):  
Yong Zhao ◽  
Jian Huang ◽  
Ying Zhao ◽  
Yi Xiong Wu
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Weld Joint ◽  
Welding Speed ◽  
Heat Input ◽  
Laser Power ◽  
Weld Zone ◽  
Lap Joints ◽  
Lap Joint ◽  
The Difference

Microstructures and mechanical properties of welded Ti-6Al-4V alloy lap joints are discussed under different parameter conditions of laser welding. The results reveal that the fusion zone consists mainly of acicular α＇martensite. The shear strength of the lap joint reaches a maximum of 836MPa at a laser power of 4kW and welding speed of 2.3m/min. When the laser power is 4kW and the welding speed is 2.1m/min, microstructures of weld joint become coarse and the shear strength falls to 736MPa. The microhardness value in the weld zone is the highest and it gradually reduces from the weld center to base metal due to the difference of microstructure. When the weld heat input is constant, larger laser power has resulted in growth of the grain and the decrease of shear strength and microhardness of lap joints.

scholarly journals Microstructural Characterization and Mechanical Properties of Fiber Laser Welded CP-Ti and Ti-6Al-4V Similar and Dissimilar Joints

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 747 ◽  
Author(s):  
Alireza Abdollahi ◽  
Ahmed Shaheer Ahnaf Huda ◽  
Abu Syed Kabir
Keyword(s):  
Mechanical Properties ◽  
Fiber Laser ◽  
Welding Speed ◽  
Heat Input ◽  
Laser Power ◽  
Pure Titanium ◽  
Microstructural Characterization ◽  
Welding Parameters ◽  
Dissimilar Joints ◽  
Cp Ti

In this research, the microstructures and mechanical properties of similar and dissimilar autogenous joints of 3 mm thick commercially pure titanium (CP-Ti) and Ti-6Al-4V welded by ytterbium fiber laser (Yb:YAG) were investigated. Two sets of laser power and welding speed were selected in such a way that the heat input remained constant. Microstructural characterization of the joints was investigated by an optical microscope, and mechanical properties were determined by hardness and tensile tests. The only defects found were porosity and underfill, and no signs of lack of penetration and solidification cracks were observed in any of the joints. Microstructural evaluation of the fusion zone (FZ) showed that in similar Ti-6Al-4V joint, a supersaturated nonequilibrium α′ martensite was formed due to rapid cooling associated with laser welding. In similar CP-Ti, coarse equiaxed grains were observed in the FZ. Unlike the similar joints, a clear interface was observed between the heat-affected zone (HAZ) and the FZ in both the CP-Ti and Ti-6Al-4V sides in dissimilar joints. Among all the joints with different weld parameters, similar Ti-6Al-4V showed the highest strength and the lowest ductility. In similar CP-Ti and dissimilar joints, fractures took place in the CP-Ti base metal, but all the Ti-6Al-4V similar joints failed in the FZ. Significant changes in the strength and hardness with varying laser power and welding speed implied that the mechanical properties of the weld fusion zones were not entirely governed by the heat input but were also affected by individual welding parameters.

scholarly journals Study on shear properties of riveted lap joints of aircraft fuselage with different hole diameters

2021 ◽  
Author(s):  
Ming Li ◽  
Wei Tian ◽  
Wenhe Liao ◽  
Junshan Hu ◽  
Changrui Wang
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Shear Strength ◽  
Lap Joints ◽  
Hole Diameter ◽  
Lap Joint ◽  
Shear Properties ◽  
Riveted Lap Joints ◽  
Element Method

Abstract Riveting is the most important way to connect metal sheets, which is widely used in the connection of aircraft components. In this paper, the effect of different hole diameters on the shear properties of riveted lap joints were studied from the perspective of practical application. Considering the symmetry and the calculation time of the model, a 2D axisymmetric finite element method is established with the help of ABAQUS commercial finite element software, the validity of the finite element model is verified by experiment tests. Because the interference distribution has an important influence on the mechanical properties of riveted lap joints, the interference distribution and material flow characteristics in riveting process are analyzed in detail by using finite element method, and the shear characteristics of riveted lap joints in tensile process are explained. The variation of hole diameter with shear force under different squeeze force was obtained by shear test in order to explain the effect of hole diameter on the shear mechanical properties of riveted lap joint. In addition, the fracture mode and microstructure of the rivet shank were characterized by SEM and the formation process of brittleness and plastic fracture is discussed. Finally, the shear failure mechanism of riveted lap joint is analyzed in detail to provide guidance for engineering application. The test results show that all the specimens are both brittle and plastic mixed fracture modes of rivet shank, and the shear strength of the rivet increases with the increase of the hole diameter. Compared with increasing the squeeze force, increasing the hole diameter can effectively improve the shear strength of the riveted lap joint.

Tensile shear strength of UF- and MUF-bonded veneer related to data of adhesives and cell walls measured by nanoindentation

Holzforschung ◽  
2010 ◽  
Vol 64 (3) ◽  
Author(s):  
Frank Stöckel ◽  
Johannes Konnerth ◽  
Wolfgang Kantner ◽  
Johann Moser ◽  
Wolfgang Gindl
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Bond Strength ◽  
Cell Walls ◽  
Urea Formaldehyde ◽  
Lap Joints ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Interphase Cell ◽  
Cure Time

Abstract The tensile shear strength of veneer lap joints was characterised. The joints were produced with an Automated Bonding Evaluation System (ABES) using urea-formaldehyde (UF) as well as melamine-urea-formaldehyde (MUF) adhesive formulated for particleboard production. At a fixed heating temperature of 110°C, a systematic increase in bond strength was observed for both adhesives with increasing cure time. The absolute bond strength was significantly higher for MUF compared to UF. Nanoindentation experiments with the same specimens used for ABES revealed a very hard, stiff and brittle character of the UF resin, whereas the MUF proved significantly less hard and stiff, and less brit-tle. Wood cell walls in contact with adhesive, i.e., where adhesive penetration into the cell wall was assumed, showed significantly altered mechanical properties. Such cell walls were harder, stiffer and more brittle than unaffected reference cell walls. These effects were slightly more pronounced for UF than for MUF. Comparing UF and MUF, the micro-mechanical properties of cured adhesive and interphase cell walls confirm earlier observations that tougher adhesives can lead to higher macroscopic bond strength. In strong contrast to that, no obvious correlation was found between micromechanical properties and the strong cure time dependence of macroscopic bond strength.

Numerical Analysis of Solidification Behavior during Laser Welding Nickel-Based Single-Crystal Superalloy Part: II Crystallography-Dependent Supersaturation of Liquid Aluminum

2021 ◽  
Vol 1018 ◽  
pp. 13-22
Author(s):  
Zhi Guo Gao
Keyword(s):  
Laser Welding ◽  
Single Crystal ◽  
Weld Pool ◽  
Welding Speed ◽  
Heat Input ◽  
Laser Power ◽  
Liquid Aluminum ◽  
Dendrite Growth ◽  
Solidification Cracking ◽  
Solid Liquid Interface

The thermal metallurgical modeling of liquid aluminum supersaturation was further developed through couple of heat transfer model, dendrite selection model, multicomponent dendrite growth model and nonequilibrium solidification model during three-dimensional nickel-based single-crystal superalloy weld pool solidification. The welding configuration plays more important role in supersaturation of liquid aluminum, morphology instability and nonequilibrium partition behavior. The bimodal distribution of liquid aluminum supersaturation along the solid/liquid interface is crystallographically symmetrical about the weld pool centerline in (001) and [100] welding configuration. The distribution of liquid aluminum supersaturation along the solid/liquid interface is crystallographically asymmetrical throughout the weld pool in (001) and [110] welding configuration. Optimum low heat input (low laser power and high welding speed) with (001) and [100] welding configuration is more favored to predominantly promote epitaxial [001] dendrite growth to reduce the metallurgical factors for solidification cracking than that of high heat input (high laser power and slow welding speed) with (001) and [110] welding configuration. The lower the heat input is used, the lower supersaturation of liquid aluminum is imposed, and the smaller size of vulnerable [100] dendrite growth region is incurred to ameliorate solidification cracking susceptibility and vice versa. The overall supersaturation of liquid aluminum in (001) and [100] welding configuration is beneficially smaller than that of (001) and [110] welding configuration regardless of heat input, and is not thermodynamically relieved by gamma prime γˊ phase. (001) and [110] welding configuration is detrimental to weldability and deteriorates the solidification cracking susceptibility because of unfavorable crystallographic orientations and alloying aluminum enrichment. The mechanism of asymmetrical solidification cracking because of crystallography-dependent supersaturation of liquid aluminum is proposed. The eligible solidification cracking location is particularly confined in [100] dendrite growth region. Moreover, the theoretical predictions agree well with the experiment results. The useful modeling is also applicable to other single-crystal superalloys with similar metallurgical properties for laser welding or laser cladding. The thorough numerical analyses facilitate the understanding of weld pool solidification behavior, microstructure development and solidification cracking phenomena in the primary γ phase, and thereby optimize the welding conditions (laser power, welding speed and welding configuration) for successful crack-free laser welding.

Investigation on the effects of the joint type on the driven out bead in the welded pipes produced by high-frequency induction welding

2020 ◽  
pp. 146442072097343
Author(s):  
M Ghaffarpour ◽  
D Akbari ◽  
H Moslemi Naeini
Keyword(s):  
Mechanical Properties ◽  
Weld Joint ◽  
High Frequency ◽  
Weld Zone ◽  
Welding Process ◽  
Solid Material ◽  
Outer Diameter ◽  
Metallurgical Properties ◽  
Semi Solid ◽  
High Frequency Induction

In this paper, the effects of the joint type on the driven-out bead of the roll-formed pipes, welded by high-frequency induction welding process are studied. The main goal is to predict and reduce the volume of the bead driven out in the weld seam. Moreover, it aims to move the semi-solid bead during welding to the outer diameter of the pipe. This study has two prior aims: to produce a defect-free joint and to improve the mechanical and metallurgical properties. In order to optimize the weld joint, various joint types have been investigated by experimental tests and simulation. Lastly, destructive tests were used to determine if the desired mechanical properties of the weld joint were obtained. The metallurgical properties and the derivation of the semi-solid material in the weld zone have both been investigated in terms of microstructure. According to the results, the proper joint type improves the mechanical properties by 5% and reduces the volume of the weld bead about 45%.

Modeling of Weld Lap-Shear Strength for Laser Transmission Welding of Thermoplastic Using Artificial Neural Network

2012 ◽  
Vol 445 ◽  
pp. 454-459 ◽  
Author(s):  
M.R. Nakhaei ◽  
N.B. Mostafa Arab ◽  
F. Kordestani
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Shear Strength ◽  
Laser Welding ◽  
Process Parameters ◽  
Welding Speed ◽  
Laser Power ◽  
Laser Transmission Welding ◽  
Lap Shear Strength ◽  
Lap Shear

Laser welding of plastic materials has a wide range of applications in the packaging, medical, electronics and automobile industries provided it can predict high quality welds compared with other joining methods. Laser welding process parameters can affect the quality of welds. In this paper, Artificial Neural Network (ANN) is used to model the effects of laser power, welding speed, clamp pressure and stand-off distance on weld lap-shear strength in laser transmission welding (LTW) of acrylic (polymathy methacrylate). A set of experimental data on diode laser weld lap-shear strengths was used to train and test the ANN from which the neurons relations were gradually extracted to develop a model. The developed ANN model can be used for the analysis and prediction of the complex relationships between the above mentioned process parameters and weld lap-shear strength. The results indicated that increase in laser power and clamp pressure increases the weld lap-shear strength whereas welding speed and stand off distance had a decreasing affect on shear strength at high value.

Shear Strength and Fracture Location of Dissimilar A6063 Aluminum Alloy and SUS430 Stainless Steel Lap Joint

2018 ◽  
Vol 773 ◽  
pp. 196-201 ◽  
Author(s):  
Paiboon Yaemphuan ◽  
Surat Triwanapong ◽  
Kittipong Kimapong
Keyword(s):  
Stainless Steel ◽  
Shear Strength ◽  
Welding Speed ◽  
Joint Interface ◽  
Tensile Shear Strength ◽  
Fracture Path ◽  
Lap Joint ◽  
Tensile Shear ◽  
Rotating Speed ◽  
Tilted Angle

In this paper, friction stir welding (FSW) was used to weld the dissimilar A6063 Aluminum/SUS430 stainless steel lap joint with various parameter setting in a welding process. The setting included a rotating speed between 125-750 rpm, a welding speed between the 25-175 mm/min and 0-5 degrees of tool tilted angle. The welded lap joints were systematically examined in regard of the tensile-shear strength, the fracture path, and microstructure. The experimental results were concluded as follows. The decrease in the welding heat input generated from the low rotating speed and the high welding resulted in decreasing of the shear strength. A degree of a tool tilted angle affected a shear strength, and a change in the strength came from the different rate in material combination at the joint interface. The increase in a tensile-shear strength occurred for specimens produced in 0-2 degrees of a tool tilted angle while 3-5 degrees affected in decreasing. The highest shear strength of 11,870 N was obtained when the lap joint was produced by the rotating speed of 500 rpm, the welding speed of 50 mm/min and the tool tilted angle at 2 degrees. The fracture path found in the specimen with the maximum shear strength was located in the Al stirred zone, not in the joint interface.

scholarly journals The Effect of Welding Speed on the Micromorphology and Mechanical Properties of Laser-Sealed Vacuum Flat Glazing Joints

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Hong Miao ◽  
Chong Li ◽  
Qiang He ◽  
Shanwen Zhang ◽  
Yanjun Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Shear Strength ◽  
Welding Speed ◽  
Theoretical Basis ◽  
Interface Reaction ◽  
Input Energy ◽  
Wetting Layer ◽  
Vacuum Glazing ◽  
Sealing Layer

To explore the effect of welding speed on the micromorphology and mechanical properties of the laser-welded vacuum plate glazing joints, this paper introduced the research status of the laser welding vacuum glazing and then carried out the preparation for experimental materials. This paper also analyzed the microstructure, the cause of the pores, and the mechanical properties of the sealing layer. The results show that the smaller the welding speed is, the more fully the solder melts. When the welding speed is 80 mm/min, the sealing layer generates the large thermal stress due to excessive laser input energy, which results in many connected cracks in the sealing layer. The porosity of the sealing layer increases with the increase of the welding speed. The thickness of the interface reaction wetting layer decreases with the increase of the welding speed. The hardness, tensile strength, and shear strength of the sealing layer will increase first and then decrease with the increase of welding speed. These studies can provide the theoretical basis for laser sealing manufacturing of vacuum plate glazing.

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