Effect Of Electromagnetic Vibration Research Articles

Effect of electromagnetic vibration on the microstructure of direct chill cast Al-Zn-Mg-Cu alloy

An electromagnetic vibration was achieved by the combined application of an alternating magnetic field and a stationary magnetic field during direct chill (DC) casting process. The ingots with 200 mm in diameter were prepared under the influence of electromagnetic vibration. The effect of electromagnetic vibration on the microstructure of an Al-Zn-Mg-Cu alloy was studied. The results showed that electromagnetic vibration has a significant effect on the solidification behaviour, under the influence of electromagnetic vibration during DC casting process, the microstructure is significantly refined and the uniformity of microstructure is evidently improved. This paper introduces the DC casting technology with the application of electromagnetic vibration, presents these results and gives corresponding discussions.

Newly Developed Technique to Eliminate Hot Cracking with Electromagnetic Vibration for Joining of 2024 Aluminum Alloy

In this study, the effect of electromagnetic vibration on joining of aluminum alloy 2024 was investigated. Simultaneously applying a static magnetic field and alternating electrical current passing through a conductor produced electromagnetic vibration. Joining was accomplished using constant electric current (60 A) and the magnetic flux of 75, 110, and 145 mT in the presence of argon gas. After joining, samples were cooled first by argon gas as a shielding gas and then by water. The microstructure and mechanical properties of the welded samples were studied for different electromagnetic vibrations. The optimum microstructure and mechanical properties were obtained when applied electromagnetic vibration was produced at 60 A and 145 mT. The average particle size of the resulting dendrites when welding was done using the optimum conditions was approximately 65 µm. EMV technique significantly reduced the occurrence of hot cracking.

Effect of Electromagnetic Vibration on the Rheological Properties of HDPE/UHMWPE Blends and the Properties of the Blown Films

The effect of electromagnetism on the shear rate and the apparent viscosity of the high density polyethylene/ultra high molecular weight polyethylene (HDPE/UHMWPE) blends are carried out by the different processing ways of the vibration capillary rheology, which is to be discussed. The mechanical properties and surface of blown films and the blend DSC curves of the of the vibration extruder are also to be discussed. The results show that the effect of vibration on the viscosity of the blends by direct blending was prominent. The mechanical properties and surface of the blown films made under the vibration state are much better than those under the static state.

Refinement and migrating behaviors in Al-Si hypereutectic alloys solidified under electromagnetic vibration

The effects of electromagnetic vibration (EMV) on the refinement and migration of primary silicons in the Al-18 wt pct Si alloy were investigated systematically. It was found that EMV could effectively refine primary silicons. The equivalent diameter of primary silicon first decreases slowly with the current increasing from 1 A to 3 A, but then drops rapidly between 3 A and 10 A, next gradually decreases with increasing current intensity. When the EMV intensity was low, the primary silicons were agglomerated and expelled to the top of a sample, the segregation of silicon grains gradually decreased and the agglomerating phenomena disappeared with the increase of EMV intensity, and the star-like coarse primary silicons turned refined flake or square morphology. The refinement and migration of primary silicons depended on the Lorentz force, gravity and the effective viscous force.

Effects of electromagnetic vibration on the structure and mechanical properties of Al-6%Si alloy during directional solidification

The effects of electromagnetic vibration on the grain refinement in directional solidification were investigated. It was found that the electromagnetic vibration applied in the melt not only can refine grains remarkably but also can enhance both tensile strength and ductility values of Al-6%Si alloy. SEM graphs show that coarse dendrite structure was broken up into a somewhat globular structure, and the morphology of eutectic silicon was changed from flaky to fibrous under electromagnetic vibration treatment. The refine mechanism under electromagnetic vibration was discussed.

Effect of electromagnetic vibration on the unmixed zone formation in 25Cr–35Ni heat resistant steel/Alloy 800 dissimilar welds

Electromagnetic vibration was applied to molten weld metal during welding of dissimilar welds between 25Cr–35Ni heat resistant steel and Alloy 800 superalloy. It was observed that the unmixed zone in the interface between the 25Cr–35Ni heat resistant steel and (the Alloy 82) weld filler metal was completely eliminated by high-frequency electromagnetic vibration. A complete mixing of the molten filler metal and base metal due to agitation of molten weld metal has caused the unmixed zone to be eliminated.

The Effect of Electromagnetic Vibration on the Structure Control of A356 Alloy

The structural control of A356 alloy, which was not studied among various electromagnetic processing of materials, was considered applying the alternating current and direct current magnetic flux density. The main aim of the present study is to investigate the effects of electromagnetic vibration on the macro and microstructure of A356 alloy in order to develop a new process of structural control in A356 alloy. When the electromagnetic vibration is conducted for changing the shape of primary aluminum, at low frequency (≤60Hz), the shape of dendrite is changed speroidal shape. When the electromagnetic vibration is conducted for changing the shape of eutectic silicon, a morphological change of the eutectic silicon from coarse platelet flakes to fine fiber shape is observed with EMV (Electro Magnetic Vibration) process at high frequency (≥500Hz).

The Effect of Frequency of Electromagnetic Vibration on the Micro Structure in Hypoeutectic Al-Si Alloy

The structural control of Al-Si alloy, which was not studied among various electromagnetic processing of materials, was considered applying the alternating current and direct current magnetic flux density. The main aim of the present study is to investigate the effects of electromagnetic vibration on the macro and microstructure of Al-Si alloy in order to develop a new process of structural control in Al-Si alloy. When the electromagnetic vibration is conducted for changing the shape of primary aluminum, at low frequency (≤ 60Hz), the shape of dendrite is changed speroidal shape. When the electromagnetic vibration is conducted for changing the shape of eutectic silicon, the fact that a morphological change of the eutectic silicon from coarse platelet flakes to fine fiber shape is observed with EMV (Electro Magnetic Vibration) process at high frequency(≥ 500Hz).

The Effect of Frequency of Electromagnetic Vibration on the Primary Silicon Size in Hypereutectic Al-Si Alloy

The structural control of Al-Si alloy, which was not studied among various electromagnetic processing of materials, was considered applying the alternating current and direct current magnetic flux density. The main aim of the present study is to investigate the effects of electromagnetic vibration on the control of the size of primary Si phase in order to develop a new process of structural control in Al-Si alloy. If the current density conducted for making high frequency electromagnetic vibration (EMV) (≥ 500Hz), the size of primary Si phase goes to small. If it conducted for making low frequency EMV (≤ 200Hz), the size of primary Si phase goes to large. This phenomenon considered to be related the collision, agglomeration and diffusion of silicon atoms.

The Effects of Electromagnetic Vibration on Macrosegregation in AZ80 Magnesium Alloy Billets

The effects of electromagnetic vibration on macrosegregation in AZ80 magnesium alloy billets have been investigated experimentally. Comparing to conventional direct-chill casting, the enrichment for the alloying elements close to the billet surface is significantly reduced by the electromagnetic vibration. Increasing the stationary magnetic field, i.e., increasing the intensity of the electromagnetic vibration results in uniform distributions of the metallic elements in the billet. The distribution of impurity iron has the same tendency with alloying element manganese with and without the electromagnetic vibration. The uniformity in the concentration profile of iron is higher than that for the alloying elements in the billet and increases with increasing the stationary magnetic field of the system used for generation of electromagnetic vibration.

The Effect of Electromagnetic Vibration on the Continuous Elimination of Inclusions in Molten Aluminum Alloy by Electromagnetic Force

The separation system including a DC electric field with steady magnetic field was adopted for removal of inclusion in molten Al alloy. But, very small inclusions, which less than 10 ㎛ are not eliminated. So, firstly, small inclusions are agglomerated by low frequency electromagnetic vibration. And then, we adopting the previously used electromagnetically inclusion removal process. Experiments were carried out on commercial die casting aluminum alloy A380 (JIS: ADC 10). Inclusion was separated continuously. XRF was used for compositional test and PoDFA for cleanliness test. Chemical composition of specimen was not changed and UTS, elongation and cleanliness were increased.

Effects of electromagnetic vibrations on the microstructure of continuously cast aluminium alloys

The influence of electromagnetic vibrations imposed during solidification on grain refinement in the 1085 and 2214 aluminium alloys, characterized by a narrow and a wide freezing range respectively, has been examined. The vibrations were produced by the simultaneous application of a stationary magnetic field B 0′ and a variable magnetic field B of frequency 50 Hz in the sump of continuously cast ingots. Extensive grain refinement has been observed in both alloys with increasing magnetizing force. This study shows the mean grain size obtained by this vibrational technique is always smaller than that produced by the recently developed CREM (carting, refining, electromagnetic) process.