Investigation on the coupling interaction in electron beam welded Al–Cu bimetallic sheet

2020 ◽  
pp. 146442072097669
Author(s):  
FS Li ◽  
ZC Wei ◽  
XF Li ◽  
HD Kang ◽  
Z Li ◽  
...  
Keyword(s):  
Electron Beam ◽  
Intermetallic Compounds ◽  
Fusion Zone ◽  
Molten Pool ◽  
Electron Beam Welding ◽  
Flow Behavior ◽  
Marangoni Effect ◽  
Interface Zone ◽  
Fracture Characteristics ◽  
Bimetallic Sheet

Two sound joints of Al–Cu bimetallic sheet with 6.5 mm in thickness were obtained in Cu (upper)–Al (lower) and Al (upper)–Cu (lower) welding configurations via the electron beam welding and their distinct coupling models were developed to well understand their flow behavior of the molten pool and microstructure evolution mechanisms during the electron beam welding. For the electron beam welding of the Cu–Al bimetallic sheet, liquid Al and Cu flowed into each other and fully combined in the fusion zone and the interface zone under high-temperature environment, forming large amount of intermetallic compounds. For the electron beam welding of the Al–Cu bimetallic sheet, liquid Al was floating on the Cu substrate, while liquid Cu was flowing at the bottom of the molten pool and mutually combined with liquid Al at the interface, forming a relatively small amount of intermetallic compounds. Moreover, a part of liquid Al flowed back to the seam root under the influence of the Marangoni effect. Therefore, the fusion zone and the interface zone with various phase compositions were formed in these two Al–Cu bimetallic joints and the mechanical properties of the corresponding joints were determined. Furthermore, the average tensile strengths of Cu–Al and Al–Cu bimetallic joints were 59 MPa and 67 MPa, respectively. The fracture locations of these two joints were both at the edge of the fusion zone along the Al2Cu intermetallic compound interlayer. Moreover, the fracture characteristics of these joints were mainly cleavage fracture.

Microstructural Characterization and Tensile Behavior of TA1 Titanium Alloy Sheet Welded by Electron Beam Welding

2021 ◽  
Vol 1027 ◽  
pp. 149-154
Author(s):  
Sen Dong Gu ◽  
Ji Peng Zhao ◽  
Rui Jie Ouyang ◽  
Yong Hong Zhang
Keyword(s):  
Titanium Alloy ◽  
Electron Beam ◽  
Fusion Zone ◽  
Heat Affected Zone ◽  
Electron Beam Welding ◽  
Base Material ◽  
Optical Microscope ◽  
Alloy Sheet ◽  
Tensile Behavior ◽  
Electron Backscattered Diffraction

In the present study, TA1 titanium alloy sheets with a thickness of 0.8mm were welded by electron beam welding. Microstructure of the welded region was investigated using optical microscope and electron backscattered diffraction. Then, the tensile test was conducted to analyse the tensile behavior of the welded sheets as well as the fractography of the fracture surfaces. It is shown that the mean grain size in the heat-affected zone is smaller than that in the fusion zone and base material. The strength of the base metal is lower than that of the fusion zone and heat-affected zone. The average values of the yield strength, tensile strength and elongation of the tensile specimens are 224MPa, 335MPa and 35%, respectively. In addition, the tensile specimens of the welded sheets suffer both ductile and brittle deformation during the tensile tests.

Role of Capillary and Thermocapillary Forces in Laser Polishing of Metals

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Chi Zhang ◽  
Jing Zhou ◽  
Hong Shen
Keyword(s):  
Capillary Force ◽  
Molten Pool ◽  
Continuous Wave ◽  
Flow Behavior ◽  
Marangoni Effect ◽  
Cost Effective ◽  
Underlying Mechanism ◽  
Thermocapillary Force ◽  
Laser Polishing ◽  
Coupled Heat Transfer

As one of emerging novel surface treatment techniques, laser polishing offers a cost-effective and efficient solution to reduce surface roughness of precision components at micro-/mesoscale. Although it has been applied for industrial and biomedical purposes, the underlying mechanism has not been fully revealed. This paper presents a study to understand the basic fundamentals of continuous wave fiber laser polishing of Ti6Al4V samples. A two-dimensional numerical model that coupled heat transfer and fluid flow is developed to illustrate the molten flow behavior. The roles of capillary and thermocapillary flow in the process of laser polishing are investigated to assist the understanding of the contributions of surface tension (capillary force) and Marangoni effect (thermocapillary force) in the polishing process. Capillary force dominates the molten pool at the initial stage of melting, while thermocapillary force becomes predominant when the molten pool fully develops.

Comparison of microstructure, mechanical properties, and residual stresses in tungsten inert gas, laser, and electron beam welding of Ti–5Al–2.5Sn titanium alloy

2017 ◽  
Vol 233 (7) ◽  
pp. 1336-1351
Author(s):  
Massab Junaid ◽  
Khalid Rahman ◽  
Fahd Nawaz Khan ◽  
Nabi Bakhsh ◽  
Mirza Nadeem Baig
Keyword(s):  
Electron Beam ◽  
Residual Stresses ◽  
Power Density ◽  
Fusion Zone ◽  
High Power ◽  
Electron Beam Welding ◽  
Inert Gas ◽  
High Power Density ◽  
Cooling Rates ◽  
Zone Width

Electron beam welding (EBW), pulsed Nd:YAG laser beam welding (P-LBW), and pulsed tungsten inert gas (P-TIG) welding of Ti–5Al–2.5Sn alloy were performed in order to prepare full penetration weldments. Owing to relatively high power density of EBW and LBW, the fusion zone width of EBW weldment was approximately equal to P-LBW weldment. The absence of shielding gas due to vacuum environment in EBW was beneficial to the joint quality (low oxide contents). However, less cooling rates were achieved compared to P-LBW as an increase in heat-affected zone width and partial α′ martensitic transformation in fusion zone were observed in EBW weldments. The microstructure in fusion zone in both the EBW and P-TIG weldments comprised of both acicular α and α′ martensite within the prior β grains. Hardness of the fusion zone in EBW was higher than the fusion zone of P-TIG but less than the fusion zone of P-LBW weldments due to the observed microstructural differences. Notch tensile specimen of P-LBW showed higher load capacity, ductility and absorbed energy as compared to P-TIG and EBW specimens due to the presence of high strength α′ martensite phase. Maximum sheet distortions and tensile residual stresses were observed in P-TIG weldments due to high overall heat input. The lowest residual stresses were found in P-LBW weldments, which were tensile in nature. This was owing to high power density and higher cooling rates in P-LBW operation. EBW weldment exhibited the highest compressive residual stresses due to which the service life of EBW weldment is expected to improve.

Analysis on the Weld Defects of the AZ91D Magnesium Alloy Joints

2009 ◽  
Vol 610-613 ◽  
pp. 931-935
Author(s):  
Hong Ye ◽  
Zhong Lin Yan ◽  
Bin Shen ◽  
Z.F. Xue
Keyword(s):  
Electron Beam ◽  
Magnesium Alloy ◽  
Fusion Zone ◽  
Electron Beam Welding ◽  
Boundary Surface ◽  
Incomplete Fusion ◽  
Az91d Magnesium Alloy ◽  
Process Characteristics ◽  
The Difference ◽  
Cast Magnesium

In this study, taking die-cast magnesium alloy AZ91D as investigation objects, the process characteristics of electron beam welding (EBW) was studied. The microstructure and familiar defects in the welded joints were analyzed. The main reasons of these defects were discussed. The experimental results showed that boundary surface between fusion zone and heat affected zone in the joint of AZ91D magnesium alloy by electron beam welding is obvious, the fusion zone (FZ) consisted of fine-equiaxed grain. Pore and crack are the main defects in AZ91D magnesium alloy joints. Magnesium has higher hydrogen solubility in liquid than in solid. The difference in the solubility between the solid and liquid phase is the major reason of the pore of magnesium alloys during welding. The crack was caused because of α + β-Mg17Al12 phase with low melting point and pores in the fusion zone. There were other defects found in the joints such as incomplete fusion and penetration.

Mechanical Properties of Forged Ti-6Al-4V Structure by Electron Beam Welding

2012 ◽  
Vol 455-456 ◽  
pp. 308-313
Author(s):  
Hong Yu Qi ◽  
Jian Xie ◽  
Shao Lin Li ◽  
Xiao Guang Yang
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Fusion Zone ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Base Material ◽  
Structure Design ◽  
Large Gradient ◽  
Welded Structure ◽  
Aero Engine

The blisk (bladed disk) is a new structural component of the modern aero-engine and plays an important role in improving its performance. Ti-6Al-4V alloy joints welded by electron beam have been widely used for compressor blisk in advanced aero engine. It is necessary to analyze microstructure and mechanical properties of Ti-6Al-4V welded structure by electron beam welding (EBW) for failure analysis and structure design of blisk. Microstructure of Ti-6Al-4V welded structure by EBW was investigated by microscopic observation and micro indentation testing. Experiment results show grain coarsening in fusion zone (FZ) and heat affected zone (HAZ) appears large gradient organization structure, which presents significant local heterogeneity. On the centerline perpendicular to the welding direction, Vickers microhardness was measured in increments of 1mm, 0.5mm, 0.25mm and 0.1mm. Due to the presence of martensite, microhardness of the fusion zone is about 20% higher than that of the base material. The size of joints in different regions was acquired, 2.5 to 3.0-mm-wide in FZ and about 0.7-mm-wide in HAZ respectively. Three different types of EBW samples were designed for tensile test, including welded structure, welded joint and base material. Three different stress-strain curves of specimens were acquired, including welded joint. The experiment data indicates that the tensile strength of welded joints is 8% more than that of the base metal.

Sign in / Sign up

Export Citation Format

Share Document