Effect of forming conditions on mechanical properties of rheoformed thin plates with microchannels using electromagnetic stirring

The latest trend in the cell phone component industry to use aluminium and magnesium alloys has resulted in the advanced processing technologies. Semi-solid forming process that is advantageous for the mass production of thin parts with complex shapes have been of interest as a promising tool for near net-shape manufacturing. This study describes a semi-solid forming process for the development of a 1 mm-thick cell phone case by using the rheological material prepared by electromagnetic stirring equipment. Thus, a new type of die design for indirect rheoforging was proposed to efficiently control the primary α-Al phase particles in the thin part under rheological conditions. Their microstructure and mechanical properties were investigated and compared to parts produced without electromagnetic stirring. Those products fabricated by electromagnetic stirring had better mechanical properties and globular microstructures than those fabricated without electromagnetic stirring. Several processing parameters such as punch velocity (30 mm/s), punch pressure (75–250 MPa), stirring time (10 s), and solid fraction (0–20%) were used. The optimal condition that resulted in a defect-free component with the improved mechanical properties was explained and discussed.

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Structure and Mechanical Properties of Injection Moulded CF/LCP Thin Plates

Polymers and Polymer Composites ◽

10.1177/096739110401200305 ◽

2004 ◽

Vol 12 (3) ◽

pp. 207-220 ◽

Cited By ~ 1

Author(s):

Fumiaki Baba ◽

Akihiro Fujita ◽

Chimyon Gon ◽

Asami Nakai ◽

Hiroyuki Hamada

Keyword(s):

Mechanical Properties ◽

Thin Plates

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Effect of UDC Casting on Hot Deformation Behavior and Properties of 2A14 Aluminum Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.944.46 ◽

2019 ◽

Vol 944 ◽

pp. 46-51 ◽

Cited By ~ 1

Author(s):

Yang Qiu ◽

Zhi Feng Zhang ◽

Hao Dong Zhao ◽

Bao Li ◽

Chun Sheng Chen

Keyword(s):

Mechanical Properties ◽

Aluminum Alloy ◽

Deformation Behavior ◽

Direct Chill ◽

Electromagnetic Stirring ◽

Ring Rolling ◽

Compression Tests ◽

Hot Deformation Behavior ◽

Dislocation Glide ◽

Dominant Deformation Mechanism

Uniform direct chill (UDC) casting is coupled annular electromagnetic stirring and intercooling, having been utilized for the preparation of large-sized aluminum alloy billet. In this paper, the UDC casting was applied to 2A14 aluminum alloy billets with a diameter of 584 mm. Hot compression tests, cogging and ring rolling procedures were carried out for the billets, respectively. The results show that during the deformation temperature of 420 °C and the strain rate of 0.01 s−1 to 10 s−1, the flow stresses of different positions are higher and more stable in the UDC casting billet than in the normal direct chill (NDC) casting billet. The dislocation glide is the dominant deformation mechanism of 2A14 aluminum alloy. Meanwhile, the UDC casting significantly improves the mechanical properties of the rolled rings in tangential and axial directions compared with the NDC casting.

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Effect of Electromagnetic Stirring on the Microstructure and Properties of Fe-Cr-Co Steel

Materials ◽

10.3390/ma11081437 ◽

2018 ◽

Vol 11 (8) ◽

pp. 1437

Author(s):

Lin Zhang ◽

Yuhang Hou ◽

Xiao Guo ◽

Zhaolong Xiang ◽

Engang Wang

Keyword(s):

Mechanical Properties ◽

Volume Fraction ◽

Cobalt Content ◽

Calculated Phase Diagram ◽

Eutectic Structure ◽

Chromium Steel ◽

Electromagnetic Stirring ◽

High Temperature Strength ◽

Consequent Improvement ◽

M23c6 Carbides

High chromium steel has been synthesized by an induction furnace adopting electromagnetic stirring (EMS). Varying amounts of cobalt was added to obtain 3, 6, and 12% Co in the steel. The melt was allowed to solidify with or without EMS in a rotary magnetic field. The effects of the varying cobalt content and the stirring have been characterized by the microstructural evolution and the consequent improvement in mechanical properties. The application of a rotary EMS during solidification has shown a significant effect on the grain refining, the reduction of element segregation, the promotion of eutectic volume fraction, and the consequent improvement of mechanical properties, including hardness and high-temperature strength. The formation mechanism of the eutectic structure and the precipitation of M7C3 and M23C6 carbides was discussed according to the calculated phase diagram. The increment of cobalt content improved the eutectic volume fraction. Cobalt addition also enhanced the hardness and the yield tensile strength, provided that the ingot structure was homogenized by the EMS.

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Microstructural Evolution and Mechanical Properties of Friction Stir Welded Butt Joints of 5A06 Alloy Ultra-Thin Sheets

Materials ◽

10.3390/ma12233906 ◽

2019 ◽

Vol 12 (23) ◽

pp. 3906 ◽

Cited By ~ 2

Author(s):

Yang Han ◽

Xiaoqing Jiang ◽

Tao Yuan ◽

Shujun Chen ◽

Dongxiao Li ◽

...

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Grain Boundaries ◽

Microstructural Evolution ◽

Welding Speed ◽

Base Material ◽

Thin Plates ◽

Al Alloy ◽

Minimum Thickness ◽

Friction Stir

Ultra-thin plates have great potential for applications in aircraft skin, the packaging industry, and packaging of electronic products. Herein, 1 mm-thick 5A06 Al alloy was welded with friction stir welding. The microstructural evolution of the welds was investigated in detail with optical microscopy, scanning electron microscopy, and electron backscatter diffraction. The results showed that the friction stir welds of 1 mm-thick 5A06 Al alloy were well formed without obvious defect and with a minimum thickness reduction of 0.025 mm. Further, the grain size and the proportion of low-angle grain boundaries decreased with decreasing welding speed, because of the increasing degree of dynamic recrystallization. Among all of the welded joints, the welding speed of 100 mm/min yielded the smallest grain size and the highest proportion of high-angle grain boundaries, and thus the best mechanical properties. Specifically, the tensile strength of the joint was greater than that of the base material, while the elongation reached 80.83% of the base material.

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The δ Phase Precipitation of an Inconel 718 Superalloy Fabricated by Electromagnetic Stirring Assisted Laser Solid Forming

Materials ◽

10.3390/ma12162604 ◽

2019 ◽

Vol 12 (16) ◽

pp. 2604 ◽

Cited By ~ 4

Author(s):

Lyu ◽

Liu ◽

Hu ◽

Yang ◽

Huang ◽

...

Keyword(s):

Mechanical Properties ◽

Electromagnetic Field ◽

Field Intensity ◽

Inconel 718 ◽

Phase Changes ◽

Electromagnetic Stirring ◽

The Core ◽

Laser Solid Forming ◽

Δ Phase ◽

Inconel 718 Superalloy

Fabricating an Inconel 718 superalloy using electromagnetic stirring assisted laser solid forming (EMS-LSF) is a novel method to modify its microstructure and mechanical properties by consuming the Nb element in the γ phase to alleviate interdendritic segregation. The precipitate of the δ phase at 950 °C after EMS-LSF can help to achieve the uniform diffusion of Nb, and can also improve its mechanical properties. The precipitation behavior of the δ phase in an EMS-LSF Inconel 718 superalloy with different heat treatment processes has been investigated. The results show that the morphology of the δ phase changes from rod-like to a long-needle shape and tends to grow from the inter dendrite to the core dendrite with electromagnetic field intensity increasing, which is accompanied by the “cutting” and “dissolution” of the Laves phase. Through precipitation kinetics analysis, the precipitation rate of the δ phase is seen to increase with the electromagnetic field intensity increasing. Under a combination of electromagnetic stirring and laser solid forming, the microhardness of the Inconel 718 samples increased slightly due to the fact that a higher content of Nb was distributed in the core dendrite resulting from the serious convection of liquid metal, which can strengthen the matrix.

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