scholarly journals Effects of Different Types of Interlayers on the Interfacial Reaction Mechanism at the Cu Side of Al/Cu Lap Joints Obtained by Laser Welding/Brazing

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7797
Author(s):  
Zhu Ruican ◽  
Guo Shixiong ◽  
Huang Chao ◽  
Lei Zhenglong ◽  
Zhang Xinrui ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reaction Mechanism ◽  
Laser Welding ◽  
Interfacial Reaction ◽  
Joint Strength ◽  
Ternary Phase ◽  
Lap Joints ◽  
Wetting Ability ◽  
Composite Layers ◽  
Different Types

The influence of tin foil and Ni coatings on microstructures, mechanical properties, and the interfacial reaction mechanism was investigated during laser welding/brazing of Al/Cu lap joints. In the presence of a Zn-based filler, tin foil as well as Ni coating strengthened the Al/Cu joints. The tin foil only slightly influenced the joint strength. It considerably improved the spreading/wetting ability of the weld filler; however, it weakened the bonding between the seam and the Al base metal. The Ni coating considerably strengthened the Al/Cu lap joints; the highest tensile strength was 171 MPa, which was higher by 15.5% than that of a joint without any interlayer. Microstructure analysis revealed that composite layers of Ni3Zn14–(τ2 Zn–Ni–Al ternary phase)–(α-Zn solid solution)–Al3Ni formed at the fusion zone (FZ)/Cu interface. Based on the inferences about the microstructures at the interfaces, thermodynamic results were calculated to analyze the interfacial reaction mechanism. The diffusion of Cu was limited by the Ni coating and the mutual attraction between the Al and Ni atoms. The microstructure comprised Zn, Ni, and Al, and they replaced the brittle Cu–Zn intermetallic compounds, successfully strengthening the bonding of the FZ/Cu interface.

scholarly journals Laser Welding on Cerclage Wire Joining in Femur Surgery

2020 ◽  
Vol 10 (7) ◽  
pp. 2407
Author(s):  
Nutchanat Thongchuea ◽  
Eakkachai Warinsiriruk ◽  
Yin-Tien Wang
Keyword(s):  
Stainless Steel ◽  
Laser Welding ◽  
Fiber Laser ◽  
Joint Strength ◽  
Welding Process ◽  
Lap Joints ◽  
Charge Voltage ◽  
Promising Alternative ◽  
Cerclage Wire ◽  
Multiple Frequencies

Stainless steel wires with fiber-laser welding on lap joints are first proposed in this study to be used as cerclage wire joints for modern femur surgery, because of their potentially larger joint strength and less loosening failure than traditional joint devices. In this feasibility study, an experiment was set up to determine adequate parameters for the laser welding process in order to ensure that the wire joint of cerclage has good weld appearance, free oxidation, and suitable joint strength. A stainless steel wire 316L with a diameter of 1.6 mm, flare-welded on lap joint was used in the experiment as a specimen cerclage wire joint. Two major effective parameters were chosen for controlling a suitable fusion weld, including charge voltage and multiple frequencies of the laser irradiation. The adequate area of the laser parameters was determined from the experiment, including the ranges of charge voltage, multiple frequencies, and pulse width. The suitable welded lengths of specimens were also studied in the mechanical test to validate the joint strength. Suggested welded length has a better tensile strength than traditional cerclage joints. The paper concludes that the stainless wire joints with a fiber laser weld represents a promising alternative to traditional cerclage joint devices for modern femur surgery.

Influence of electrodeposited Cu-Ni layer on interfacial reaction and mechanical properties of laser welded-brazed Mg/Ti lap joints

2019 ◽  
Vol 37 ◽  
pp. 251-265 ◽  
Author(s):  
S.T. Auwal ◽  
S. Ramesh ◽  
Zequn Zhang ◽  
Jinge Liu ◽  
Caiwang Tan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Interfacial Reaction ◽  
Lap Joints

Effect of welding speed on microstructure and mechanical properties of titanium alloy/stainless steel lap joints during cold metal transfer method

2020 ◽  
Vol 117 (5) ◽  
pp. 506
Author(s):  
Gang Li ◽  
Shengyu Xu ◽  
Xiaofeng Lu ◽  
Xiaolei Zhu ◽  
Yupeng Guo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Fusion Zone ◽  
Welding Speed ◽  
Joint Strength ◽  
Metal Transfer ◽  
Lap Joints ◽  
Cold Metal Transfer ◽  
Microstructure And Mechanical Properties ◽  
Cold Metal

Cold metal transfer (CMT) technique is developed for lap joining of titanium (Ti) alloy to stainless steel (SS) with CuSi3 filler wire. The effect of welding speed on the microstructure and mechanical properties of Ti/SS lap joints is investigated. The results indicate that the wetting angle of the lap joints gradually increases and the weld width decreases with increasing the welding speed. It is found that many coarse phases in the fusion zone are rich in Ti, Fe and Si etc, inferring as Fe–Si–Ti ternary phase and/or Fe2Ti phase at low welding speed. Many fine spherical particles in the fusion zone are considered as iron-rich particles at high welding speed. The transition layer are exhibited at the Ti–Cu interface. With increasing the heat input, the intermetallic layer becomes thicker. A variety of brittle intermetallic compounds (IMCs) are identified in the lap joints. The shear strength of the joints increases with increasing the welding speed. Two fracture modes occur in the lap joints at low welding speed. Thicker reaction layer causes brittle fracture and poor joint strength. The Fe–Ti–Si and Fe2Ti phase within the fusion zone are detrimental to the joint strength. The fracture surface of the joints is dominated by smooth surface and tear pattern at high welding speed. The fracture mode of the joints is merely along the Ti–Cu interface.

EFFECT OF ZINC DITHIOCARBAMATES AND THIAZOLE-BASED ACCELERATORS ON THE VULCANIZATION OF NATURAL RUBBER

2012 ◽  
Vol 85 (1) ◽  
pp. 120-131 ◽  
Author(s):  
Md. Najib Alam ◽  
Swapan Kumar Mandal ◽  
Subhas Chandra Debnath
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Reaction Mechanism ◽  
Natural Rubber ◽  
High Performance ◽  
Binary Systems ◽  
Synergistic Activity ◽  
Tetramethylthiuram Disulfide

Abstract Several zinc dithiocarbamates (ZDCs) as accelerator derived from safe amine has been exclusively studied in the presence of thiazole-based accelerators to introduce safe dithiocarbamate in the vulcanization of natural rubber. Comparison has been made between conventional unsafe zinc dimethyldithiocarbamate (ZDMC) with safe novel ZDC combined with thizole-based accelerators in the light of mechanical properties. The study reveals that thiuram disulfide and 2-mercaptobenzothiazole (MBT) are always formed from the reaction either between ZDC and dibenzothiazyledisulfide (MBTS) or between ZDC and N-cyclohexyl-2-benzothiazole sulfenamide (CBS). It has been conclusively proved that MBT generated from MBTS or CBS reacts with ZDC and produces tetramethylthiuram disulfide. The observed synergistic activity has been discussed based on the cure and physical data and explained through the results based on high-performance liquid chromatography and a reaction mechanism. Synergistic activity is observed in all binary systems studied. The highest tensile strength is observed in the zinc (N-benzyl piperazino) dithiocarbamate-accelerated system at 3:6 mM ratios. In respect of tensile strength and modulus value, unsafe ZDMC can be successfully replaced by safe ZDCs in combination with thiazole group containing accelerator.

scholarly journals Effect of Micro Solidification Crack on Mechanical Performance of Remote Laser Welded AA6063 Fillet Lap Joint in Automotive Battery Tray Construction

2021 ◽  
Vol 11 (10) ◽  
pp. 4522
Author(s):  
Tianzhu Sun ◽  
Pasquale Franciosa ◽  
Conghui Liu ◽  
Fabio Pierro ◽  
Darek Ceglarek
Keyword(s):  
Laser Welding ◽  
Fusion Zone ◽  
Aluminium Alloys ◽  
Mechanical Performance ◽  
Lap Joints ◽  
Fatigue Durability ◽  
Micro Cracks ◽  
Remote Laser Welding ◽  
Weld Fatigue ◽  
Weld Root

Remote laser welding (RLW) has shown a number of benefits of joining 6xxx aluminium alloys such as high processing speed and process flexibility. However, the crack susceptibility of 6xxx aluminium alloys during RLW process is still an open problem. This paper experimentally assesses the impact of transverse micro cracks on joint strength and fatigue durability in remote laser welding of AA6063-T6 fillet lap joints. Distribution and morphology of transverse micro cracks were acquired by scanning electron microscope (SEM) on cross-sections. Grain morphology in the weld zone was determined by electron backscatter diffraction (EBSD) while static tensile and dynamic fatigue tests were carried out to evaluate weld mechanical performance. Results revealed that increasing welding speed from 2 m/min to 6 m/min did not introduce additional transverse micro cracks. Additionally, welding at 2 m/min resulted in tensile strength improvement by 30% compared to 6 m/min due to the expansion of fusion zone, measured by the throat thickness, and refinement of columnar grains near fusion lines. Furthermore, the weld fatigue durability is significantly higher when fracture occurs in weld root instead of fusion zone. This can be achieved by increasing weld root angle with optimum weld fatigue durability at around 55°.

scholarly journals The Effect of Different Types of Internal Curing Liquid on the Properties of Alkali-Activated Slag (AAS) Mortar

2021 ◽  
Vol 13 (4) ◽  
pp. 2407
Author(s):  
Guang-Zhu Zhang ◽  
Xiao-Yong Wang ◽  
Tae-Wan Kim ◽  
Jong-Yeon Lim ◽  
Yi Han
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Deionized Water ◽  
Internal Curing ◽  
Control Group ◽  
Alkali Activated Slag ◽  
Different Types ◽  
Naoh Solution ◽  
Activated Slag ◽  
Alkali Activated

This study shows the effect of different types of internal curing liquid on the properties of alkali-activated slag (AAS) mortar. NaOH solution and deionized water were used as the liquid internal curing agents and zeolite sand was the internal curing agent that replaced the standard sand at 15% and 30%, respectively. Experiments on the mechanical properties, hydration kinetics, autogenous shrinkage (AS), internal temperature, internal relative humidity, surface electrical resistivity, ultrasonic pulse velocity (UPV), and setting time were performed. The conclusions are as follows: (1) the setting times of AAS mortars with internal curing by water were longer than those of internal curing by NaOH solution. (2) NaOH solution more effectively reduces the AS of AAS mortars than water when used as an internal curing liquid. (3) The cumulative heat of the AAS mortar when using water for internal curing is substantially reduced compared to the control group. (4) For the AAS mortars with NaOH solution as an internal curing liquid, compared with the control specimen, the compressive strength results are increased. However, a decrease in compressive strength values occurs when water is used as an internal curing liquid in the AAS mortar. (5) The UPV decreases as the content of zeolite sand that replaces the standard sand increases. (6) When internal curing is carried out with water as the internal curing liquid, the surface resistivity values of the AAS mortar are higher than when the alkali solution is used as the internal curing liquid. To sum up, both NaOH and deionized water are effective as internal curing liquids, but the NaOH solution shows a better performance in terms of reducing shrinkage and improving mechanical properties than deionized water.

Sign in / Sign up

Export Citation Format

Share Document