Evolution of acoustic softening effect on ultrasonic-assisted micro/meso-compression behavior and microstructure

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.

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Analytical Prediction and Experimental Investigation of Burnishing Force in Rotary Ultrasonic Roller Burnishing Titanium Alloy Ti–6Al–4V

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4046027 ◽

2020 ◽

Vol 142 (3) ◽

Author(s):

Jian Zhao ◽

Zhanqiang Liu ◽

Bing Wang ◽

Yukui Cai ◽

Qinghua Song

Keyword(s):

Titanium Alloy ◽

Prediction Model ◽

Milling Process ◽

Analytical Prediction ◽

Ultrasonic Power ◽

Machined Surface ◽

Softening Effect ◽

Force Prediction ◽

Contact Width ◽

Acoustic Softening

Abstract Ultrasonic burnishing is usually applied to make machined surface modification. The acoustic softening effect caused by ultrasonic vibration is beneficial to the machining of difficult-to-cut materials. In the present work, a burnishing force prediction model was proposed for rotary ultrasonic burnishing of titanium alloy Ti–6Al–4V, whose surface had been machined with the face milling process. Firstly, the contact between the burnishing roller and one single milling mark was analyzed with plane strain assumption based on the Boussinesq–Flamant contact problem. Then, the effect of ultrasonic softening on the yield stress of Ti–6Al–4V was investigated. The critical contact width and contact load that the burnishing roller crushed on one single milling mark were examined to confirm the feasibility of the proposed ultrasonic burnishing force prediction model. The experimental verifications were carried out at various ultrasonic powers. The burnishing forces from experiment measurements were consistent with the calculated results from the proposed model. The mean deviations between theoretical and experimental results of the ultrasonic burnishing force were 10.4%, 12.2%, and 15.2%, corresponding to the ultrasonic power at the level of 41 W, 158 W, and 354 W, respectively.

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Re-saturation targets identified from 4D seismic softening responses in the Forties Field

Geological Society London Petroleum Geology Conference series ◽

10.1144/pgc8.25 ◽

2017 ◽

Vol 8 (1) ◽

pp. 473-483 ◽

Cited By ~ 2

Author(s):

Lyndsay Singer ◽

Grant Byerley ◽

Phil Rose

Keyword(s):

Water Saturation ◽

Water Injection ◽

Hydrodynamic Interactions ◽

Driving Mechanism ◽

Pressure Measurements ◽

Softening Effect ◽

Average Water ◽

Acoustic Softening ◽

4D Seismic ◽

Over Time

AbstractA novel 4D methodology by targeting softening responses, a decrease in impedance over time, is described from the Forties Field. It is demonstrated that these anomalies identified areas where oil had re-saturated previously swept rock. When first observed in some of the older vintages of 4D data, softening responses were dismissed as side lobes of underlying water-swept reservoirs. With improved 4D data quality, softening responses were seen to be clearly responding to an acoustic softening effect isolated in the reservoir. Pressure measurements ruled out hypotheses of gas exsolution or geomechanically induced dilatation of the overlying shale.At the time of writing 22 re-saturation targets had been drilled at Forties with an average water saturation (Sw) of 28%, close to virgin conditions. These results indicated that a previously swept sand can be re-saturated to near initial oil conditions.The driving mechanism behind the re-saturation is understood to be related to changes in both production offtake and water injection. The resulting complex hydrodynamic interactions appeared to be moving banks of oil around the field. From 2011 to year-end of 2015 re-saturation targets produced 14.6 MMBO and were a key target type at the Forties Field.

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Microscopic Study on the Mechanism of Ultrasonic Nanowelding

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.97-101.3928 ◽

2010 ◽

Vol 97-101 ◽

pp. 3928-3931 ◽

Cited By ~ 2

Author(s):

Xuan Liu ◽

Li Jie Zhao ◽

Hua Zhou

Keyword(s):

Molecular Dynamics ◽

High Frequency ◽

Field Effect ◽

Field Effect Transistors ◽

Single Wall Carbon Nanotubes ◽

Metal Electrodes ◽

Softening Effect ◽

Acoustic Softening ◽

Dynamics Method ◽

Ultrasonic Parameter

Using molecular dynamics method, the progress of bonding single-wall carbon nanotubes and metal electrodes by ultrasonic nanowelding technique is described completely at atomistic length scales. The temperature distribution in electrodes is analyzed. The maximal temperature of electrode atoms is about 570.1K. The mechanism responsible for ultrasonic nanowelding is revealed as the result of the high-frequency ultrasonic energy softening the metal and causing plastic deformation of the metal under the clamping stress because of the ‘acoustic softening effect’. The ultrasonic parameter is optimized, which is important in improving the performance of carbon nanotube field-effect transistors and building reliable nanodevices.

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Acoustic softening in metals during ultrasonic assisted deformation via CP-FEM

Materials Letters ◽

10.1016/j.matlet.2010.10.031 ◽

2011 ◽

Vol 65 (2) ◽

pp. 356-359 ◽

Cited By ~ 77

Author(s):

Amir Siddiq ◽

Tamer El Sayed

Keyword(s):

Ultrasonic Assisted ◽

Acoustic Softening

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Investigation on Microsheet Metal Deformation Behaviors in Ultrasonic-Vibration-Assisted Uniaxial Tension with Aluminum Alloy 5052

Materials ◽

10.3390/ma13030637 ◽

2020 ◽

Vol 13 (3) ◽

pp. 637 ◽

Cited By ~ 3

Author(s):

Chunju Wang ◽

Weiwei Zhang ◽

Lidong Cheng ◽

Changqiong Zhu ◽

Xinwei Wang ◽

...

Keyword(s):

Ultrasonic Vibration ◽

Thin Sheet ◽

Acoustic Energy ◽

Machining Process ◽

Residual Effects ◽

Forming Limit ◽

Uniaxial Tensile ◽

Softening Effect ◽

Deformation Ability ◽

Acoustic Softening

Ultrasonic vibration (UV) is widely used in the forming, joining, machining process, etc. for the acoustic softening effect. For parts with small dimensions, UV with limited output energy is very suitable for the microforming process and has been gaininf more and more attention. In this investigation, UV-assisted uniaxial tensile experiments were carried out utilizing GB 5052 thin sheets of different thicknesses and grain sizes, respectively. The coupling effects of UV and the specimen dimension on the properties of the material were analyzed from the viewpoint of acoustic energy in activating dislocations. A reduction of flow stress was found for the existing acoustic softening effects of UV. Additionally, the residual effects of UV were demonstrated when UV was turned off. The uniform deformation ability of thin sheet could be improved by increasing the hardening exponent with UV. The experimental results indicate that UV is very helpful in improving the forming limit in microsheet forming, e.g., microbulging and deep drawing processes.

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Microstructure and Formation Mechanism of Ultrasound-Assisted Transient Liquid Phase Bonded Magnesium Alloys with Ni Interlayer

Materials ◽

10.3390/ma12223732 ◽

2019 ◽

Vol 12 (22) ◽

pp. 3732 ◽

Cited By ~ 1

Author(s):

Yinan Li ◽

Chengfei Yang ◽

Zilong Peng ◽

Zhiyuan Wu ◽

Zhuang Cui

Keyword(s):

Shear Strength ◽

Liquid Phase ◽

Magnesium Alloys ◽

Microstructural Evolution ◽

Transient Liquid Phase ◽

Hardness Measurement ◽

Softening Effect ◽

Acoustic Softening ◽

Ultrasound Assisted ◽

Ni Interlayer

Ultrasound-assisted transient liquid phase bonding (U-TLP) has been regarded as a promising brazing process to join magnesium alloys with a Sn and Zn interlayer; however, the formation of brittle magnesium intermetallic compounds (Mg2Sn, MgZn, and MgZn2) compromises the mechanical properties of the joints. In this study, Mg alloy U-TLP joints with a Ni interlayer were evaluated based on shear strength and hardness measurement. Microstructural evolution along with ultrasonic duration time and intermetallic compound formation were characterized using X-ray diffraction and electron microscopy methods. The results show that incremental ultrasonic durations of up to 30 s lead to the microstructural evolution from the Mg2Ni layer, eutectic compounds (Mg2Ni and α-Mg) to α-Mg (Ni), accompanied by shear strength increases. The maximum value of the shear strength is 107 MPa. The role that ultrasound vibration played in brazing was evaluated, and showed that the MgO film was broken by the acoustic softening effect when the interlayer and base metal were solid. As the MgO and Mg substrate have different stress reduction τ, this plastic mismatch helps to break the oxide film. Additionally, the diffusion between the solid Mg substrate and Ni interlayer is accelerated greatly by the acoustic pressure based on the DICTRA dynamic calculation.

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