scholarly journals Ultrasonic-Assisted Semi-Solid Forming Method and Microstructure Evolution of Aluminum/Copper Brazed Joints

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 223
Author(s):  
Yin Liang ◽  
Jiruan Pan ◽  
Hua Zhang ◽  
Peng Huang ◽  
Jun Wang ◽  
...  
Keyword(s):  
Ultrasonic Vibration ◽  
Microstructure Evolution ◽  
Heat Dissipation ◽  
Welding Seam ◽  
Ultrasonic Assisted ◽  
Brazed Joints ◽  
Brazed Joint ◽  
Semi Solid ◽  
Short Time ◽  
High Frequency Induction Brazing

Aluminum/Copper dissimilar metal connection devices have been widely used in equipment manufacturing. Ultrasonic vibration assisted semi-solid brazing technology is beneficial to improve brazing quality by using the good flow ability and strong deformation resistance of brazing alloy when it is in a semi-solid state. In this study, a new ultrasound-assisted high-frequency induction brazing method was used to braze aluminum and copper dissimilar metals under non-vacuum conditions with non-prefabrication of brazing filler metal. In a short time, uniform semi-solid brazed joint was obtained. Detailed investigations on the effects of aluminum-substrate side (Abbreviated as Al side) heat dissipation rate and ultrasonic vibration duration on the microstructure evolution and mechanical properties of semisolid weld were conducted. The results show that the welding seam obtained by the modification method increases the microstructure uniformity of brazing joint.

scholarly journals Ultrasound Effect on the Microstructure and Hardness of AlMg3 Alloy under Upsetting

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1010
Author(s):  
Przemysław Snopiński ◽  
Tibor Donič ◽  
Tomasz Tański ◽  
Krzysztof Matus ◽  
Branislav Hadzima ◽  
...  
Keyword(s):  
Flow Stress ◽  
Ultrasonic Vibration ◽  
Light And Electron Microscopy ◽  
Load Flow ◽  
Forming Limit ◽  
Ultrasonic Vibrations ◽  
Softening Effect ◽  
Simultaneous Application ◽  
Ultrasonic Assisted ◽  
Acoustic Softening

To date, numerous investigations have shown the beneficial effect of ultrasonic vibration-assisted forming technology due to its influence on the forming load, flow stress, friction condition reduction and the increase of the metal forming limit. Although the immediate occurring force and mean stress reduction are known phenomena, the underlying effects of ultrasonic-based material softening remain an object of current research. Therefore, in this article, we investigate the effect of upsetting with and without the ultrasonic vibrations (USV) on the evolution of the microstructure, stress relaxation and hardness of the AlMg3 aluminum alloy. To understand the process physics, after the UAC (ultrasonic assisted compression), the microstructures of the samples were analyzed by light and electron microscopy, including the orientation imaging via electron backscatter diffraction. According to the test result, it is found that ultrasonic vibration can reduce flow stress during the ultrasonic-assisted compression (UAC) process for the investigated aluminum–magnesium alloy due to the acoustic softening effect. By comparing the microstructures of samples compressed with and without simultaneous application of ultrasonic vibrations, the enhanced shear banding and grain rotation were found to be responsible for grain refinement enhancement. The coupled action of the ultrasonic vibrations and plastic deformation decreased the grains of AlMg3 alloy from ~270 μm to ~1.52 μm, which has resulted in a hardness enhancement of UAC processed sample to about 117 HV.

Study of Microstructure Evolution during Semi-Solid Processing of an In-Situ Al Alloy Composite

2015 ◽  
Vol 30 (3) ◽  
pp. 356-366 ◽  
Author(s):  
Santosh Kumar ◽  
Prosenjit Das ◽  
Sandeep K. Tiwari ◽  
Manas K. Mondal ◽  
Supriya Bera ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Al Alloy ◽  
Alloy Composite ◽  
Semi Solid

Microstructure evolution of Al-Si semi-solid slurry by gas bubble stirring method

2011 ◽  
Vol 18 (6) ◽  
pp. 1789-1794 ◽  
Author(s):  
Lei Zhang ◽  
Xuan-pu Dong ◽  
Ji-qiang Li ◽  
Kan Li ◽  
Zong-kui Zhang ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Gas Bubble ◽  
Semi Solid

Vacuum Brazing Incoloy 800 Using the Copper Foil

2015 ◽  
Vol 1101 ◽  
pp. 99-103
Author(s):  
Cheng Yen Wang ◽  
Ren Kae Shiue
Keyword(s):  
Shear Strength ◽  
Copper Foil ◽  
Vacuum Furnace ◽  
Vacuum Brazing ◽  
Average Shear Strength ◽  
Average Shear ◽  
Incoloy 800 ◽  
Brazed Joints ◽  
Brazed Joint ◽  
Time Average

The purpose of this research is focused on vacuum furnace brazing Incoloy 800 (IN-800) using the copper filler foil. Microstructural evolution and shear strength of brazed joints for various brazing conditions has been evaluated in the experiment. The Cu-rich matrix dominates entire brazed joint. The width of Cu-rich matrix is decreased with increasing the brazing temperature and/or time. Average shear strength of the joint is approximately 215 MPa. Dimple dominated fracture is widely observed for the specimen brazed below 1160oC. However, cleavage dominated fracture is found for the specimen brazed at 1200oC. It is advised that copper brazing IN-800 alloy should be confined below 1160oC.

Evolution of microstructure of 304 stainless steel joined by brazing process

2010 ◽  
Vol 1276 ◽  
Author(s):  
F. García-Vázquez ◽  
I. Guzmán-Flores ◽  
A. Garza ◽  
J. Acevedo
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Holding Time ◽  
304 Stainless Steel ◽  
Commercial Application ◽  
Wide Range ◽  
Unique Method ◽  
Brazed Joints ◽  
Brazed Joint ◽  
Evolution Of Microstructure

AbstractBrazing is a unique method to permanently join a wide range of materials without oxidation. It has wide commercial application in fabricating components. This paper discusses results regarding the brazing process of 304 stainless steel. The experimental brazing is carried out using a nickel-based (Ni-11Cr-3.5Si-2.25B-3.5Fe) filler alloy. In this process, boron and silicon are incorporated to reduce the melting point, however they form hard and brittle intermetallic compounds with nickel (eutectic phases) which are detrimental to the mechanical properties of brazed joints. This investigation deals with the effects of holding time and brazing temperature on the microstructure of joint and base metal, intermetallic phases formation within the brazed joint as well as measurement of the tensile strength. The results show that a maximum tensile strength of 464 MPa is obtained at 1120°C and 4 h holding time. The shortest holding times will make boron diffuse insufficiently and generate a great deal of brittle boride components.

Research on Milling Force in Ultrasonic Assisted End Milling of Titanium Alloy Thin-Walled Parts

2018 ◽  
Vol 764 ◽  
pp. 252-260
Author(s):  
Feng Jiao ◽  
Cheng Lin Yao ◽  
Li Zhao ◽  
Feng Qi
Keyword(s):  
Titanium Alloy ◽  
Cutting Force ◽  
Ultrasonic Vibration ◽  
End Milling ◽  
Signal To Noise Ratio ◽  
Milling Force ◽  
Alloy Material ◽  
Ultrasonic Assisted ◽  
Thin Walled ◽  
Force Characteristics

Hard machinability of titanium alloy material and poor stiffness of thin-walled part restricted the extensive applications of titanium alloy thin-walled component in aerospace engineering. In order to increase geometric accuracy, a method of ultrasonic vibration assisted (UVA) end milling technology with workpiece vibrating in feeding direction was put forward in this paper, and the corresponding milling force characteristics in UVA milling of titanium alloy TC4 thin-walled workpiece were researched. Through theoretical analysis, the path of cutter tooth in UVA milling was analyzed. The important factors that affect milling force are obtained with the signal to noise ratio analysis. Results show that the radial cutting force in UVA milling is smaller than that in traditional milling. Cutting force fluctuate in high frequency when treated ultrasonic vibration. And the axial cutting feed is the core factor that affects the milling force. The research provides a certain reference for the precision milling of titanium alloy thin-walled parts.

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