scholarly journals Shear Punching of Amorphous Alloys under High-Frequency Vibrations

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1158 ◽  
Author(s):  
Hongzhen Li ◽  
Yuqiang Yan ◽  
Fei Sun ◽  
Kangsen Li ◽  
Feng Luo ◽  
...  

Although amorphous alloys possess many excellent properties, their practical application is limited due to the difficulty of plastic forming. In this work, an effective shear punching of amorphous alloys under high-frequency vibrations was proposed. Under the high-frequency vibration of the punch, the plastic powder was melted into a flexible punch due to the frictional heat generation effect and the viscoelastic heat effect and continued to flow downward under the extrusion of the ultrasonic head to plastically deform the amorphous alloy ribbon. The disordered structure of the amorphous alloys helps them get soft in a localized region during high-frequency vibrations, which can result in low-stress deformations that are different from amorphous alloys in the conventional state. We manufactured various shapes with area of 5 mm2 using high-frequency vibrations and a molten plastic viscous medium. The molds were shaped into the letters “B”, “M”, and “G” and the Chinese characters “工” and “大”. The shapes were made from Fe-based, Al-based, La-based, and Cu-based amorphous alloys. Our results show that shear punching of amorphous alloys under high-frequency vibrations is an effective and low-cost production method of amorphous alloy, which also provides a basis for the wide application of amorphous alloy.

Author(s):  
S. R. Rakhmanov

In some cases, the processes of piercing or expanding pipe blanks involve the use of high-frequency active vibrations. However, due to insufficient knowledge, these processes are not widely used in the practice of seamless pipes production. In particular, the problems of increasing the efficiency of the processes of piercing or expanding a pipe blank at a piercing press using high-frequency vibrations are being solved without proper research and, as a rule, by experiments. The elaboration of modern technological processes for the production of seamless pipes using high-frequency vibrations is directly related to the choice of rational modes of metal deformation and the prediction resistance indicators of technological tools and the reliability of equipment operation. The creation of a mathematical model of the process of vibrating piercing (expansion) of an axisymmetric pipe blank at a piercing press of a pipe press facility is an actual task. A calculation scheme for the process of piercing a pipe plank has been elaborated. A dependence was obtained characterizing the speed of front of plastic deformation propagation on the speed of penetration of a vibrated axisymmetric mandrel into the pipe workpiece being pierced. The dynamic characteristics of the occurrence of wave phenomena in the metal being pierced under the influence of a vibrated tool have been determined, which significantly complements the previously known ideas about the stress-strain state of the metal in the deformation zone. The deformation fields in the zones of the disturbed region of the deformation zone were established, taking into account the high-frequency vibrations of the technological tool. It has been established that the choice of rational parameters (amplitude-frequency characteristics) of the vibration piercing process of a pipe blank results in significant increase in the efficiency of the process, the durability of the technological tool and the quality of the pierced blanks.


Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 206
Author(s):  
Qiang Wang ◽  
Peng Han ◽  
Shuo Yin ◽  
Wen-Juan Niu ◽  
Le Zhai ◽  
...  

Compared with traditional crystalline materials, amorphous alloys have excellent corrosion and wear resistance and high elastic modulus, due to their unique short-range ordered and long-range disordered atomic arrangement as well as absence of defects, such as grain boundaries and dislocations. Owing to the limitation of the bulk size of amorphous alloys as structural materials, the application as functional coatings can widely extend their use in various engineering fields. This review first briefly introduces the problems involved during high temperature preparation processes of amorphous coatings, including laser cladding and thermal spraying. Cold spray (CS) is characterized by a low-temperature solid-state deposition, and thus the oxidation and crystallization related with a high temperature environment can be avoided during the formation of coatings. Therefore, CS has unique advantages in the preparation of fully amorphous alloy coatings. The research status of Fe-, Al-, Ni-, and Zr-based amorphous alloy coatings and amorphous composite coatings are reviewed. The influence of CS process parameters, and powders and substrate conditions on the microstructure, hardness, as well as wear and corrosion resistance of amorphous coatings is analyzed. Meanwhile, the deposition mechanism of amorphous alloy coatings is discussed by simulation and experiment. Finally, the key issues involved in the preparation of amorphous alloy coatings via CS technology are summarized, and the future development is also being prospected.


2021 ◽  
Author(s):  
Jingjing Yu ◽  
Bihao Hu ◽  
Chuanlan Xu ◽  
Jiazhi Meng ◽  
Shu Yang ◽  
...  

Nickel is widely researched in the electrooxidation of borohydride due to its low cost and abundant reserves, but it’s catalytic activity and stability need to be improved for practical application....


2021 ◽  
Vol 1826 (1) ◽  
pp. 012082
Author(s):  
G F Bassous ◽  
R F Calili ◽  
C R H Barbosa

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1690
Author(s):  
Jian Qiao ◽  
Peng Yu ◽  
Yanxiong Wu ◽  
Taixi Chen ◽  
Yixin Du ◽  
...  

Amorphous alloys have emerged as important materials for precision machinery, energy conversion, information processing, and aerospace components. This is due to their unique structure and excellent properties, including superior strength, high elasticity, and excellent corrosion resistance, which have attracted the attention of many researchers. However, the size of the amorphous alloy components remains limited, which affects industrial applications. Significant developments in connection with this technology are urgently needed. Laser welding represents an efficient welding method that uses a laser beam with high energy-density for heating. Laser welding has gradually become a research hotspot as a joining method for amorphous alloys due to its fast heating and cooling rates. In this compact review, the current status of research into amorphous-alloy laser welding technology is discussed, the influence of technological parameters and other welding conditions on welding quality is analyzed, and an outlook on future research and development is provided. This paper can serve as a useful reference for both fundamental research and engineering applications in this field.


2016 ◽  
Vol 32 (3) ◽  
pp. 297-311
Author(s):  
T.-Y. Zhao ◽  
H.-Q. Yuan ◽  
B.-B. Li ◽  
Z.-J. Li ◽  
L.-M. Liu

AbstractThe analysis method is developed to obtain dynamic characteristics of the rotating cantilever plate with thermal shock and tip-rub. Based on the variational principle, equations of motion are derived considering the differences between rubbing forces in the width direction of the plate. The transverse deformation is decomposed into quasi-static deformation of the cantilever plate with thermal shock and dynamic deformation of the rubbing plate under thermal shock. Then deformations are obtained through the calculation of modal characteristics of rotating cantilever plate and temperature distribution function. Special attention is paid to the influence of tip-rub and thermal shock on the plate. The results show that tip-rub has the characteristics of multiple frequency vibrations, and high frequency vibrations are significant. On the contrary, thermal shock shows the low frequency vibrations. The thermal shock makes the rubbing plate gradually change into low frequency vibrations. Because rub-induced vibrations are more complicated than those caused by thermal shock, tip-rub is easier to result in the destruction of the blade. The increasing friction coefficient intensifies vibrations of the rubbing plate. Minimizing friction coefficients can be an effective way to reduce rub-induced damage through reducing the surface roughness between the blade tip and the inner surface of the casing.


2013 ◽  
Vol 341 (4-5) ◽  
pp. 477-482 ◽  
Author(s):  
Sergey M. Ishutov ◽  
Bela I. Myznikova ◽  
Boris L. Smorodin

2013 ◽  
Vol 113 (11) ◽  
pp. 2871-2871 ◽  
Author(s):  
Pierpaolo Iodice ◽  
Rosa Grazia Bellomo ◽  
Glaugo Gialluca ◽  
Giorgio Fanò ◽  
Raoul Saggini

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