Evolution of solidification structures and mechanical properties of high-Si Al alloys under permanent magnetic stirring

Yan, Wei; Chen, Weiqing; Zhang, Senlin; Li, Bing; Li, Jing

doi:10.1016/j.matchar.2019.109894

Cited by 33 publications

(15 citation statements)

References 32 publications

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“…This could be attributed to the larger interfacial area offered by the shock waves generated from the rapid formation of cavitation bubbles in facilitating the starch diffusion [52]. On the other hand, desirable mixing to achieve higher uniformity was difficult for magnetic stirring as the stirring bar was situated at the bottom of the flask which might have resulted in lower extraction yield [59]. Similar findings in the starch extraction from Radix Puerariae was reported by Li et al [60] with an extraction yield of 45.7% achieved by ultrasound technique in 30 min and an extraction yield of 39.6% by conventional approach using magnetic stirrer in 2 h. Comparatively, the ultrasound technique is more energy and time efficient.…”

Section: Comparison Between Conventional and Ultrasound-assisted Extr...mentioning

confidence: 99%

Rapid Ultrasound-Assisted Starch Extraction from Sago Pith Waste (SPW) for the Fabrication of Sustainable Bioplastic Film

et al. 2021

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The present study was conducted to optimize the extraction yield of starch from sago (Metroxylon sagu) pith waste (SPW) with the assistance of ultrasound ensued by the transformation of extracted starch into a higher value-added bioplastic film. Sago starch with extraction yield of 71.4% was successfully obtained using the ultrasound-assisted extraction, with the following conditions: particle size <250 µm, solid loading of 10 wt.%, ultrasonic amplitude 70% and duty cycle of 83% in 5 min. The rapid ultrasound approach was proven to be more effective than the conventional extraction with 60.9% extraction yield in 30 min. Ultrasound-extracted starch was found to exhibit higher starch purity than the control starch as indicated by the presence of lower protein and ash contents. The starch granules were found to have irregular and disrupted surfaces after ultrasonication. The disrupted starch granules reduced the particle size and increased the swelling power of starch which was beneficial in producing a film-forming solution. The ultrasound-extracted sago starch was subsequently used to prepare a bioplastic film via solution casting method. A brownish bioplastic film with tensile strength of 0.9 ± 0.1 MPa, Young’s modulus of 22 ± 0.8 MPa, elongation at break of 13.6 ± 2.0% and water vapour permeability (WVP) of 1.11 ± 0.1 × 10−8 g m−1 s−1 Pa−1 was obtained, suggesting its feasibility as bioplastic material. These findings provide a means of utilization for SPW which is in line with the contemporary trend towards greener and sustainable products and processes.

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Section: Comparison Between Conventional and Ultrasound-assisted Extr...mentioning

confidence: 99%

Rapid Ultrasound-Assisted Starch Extraction from Sago Pith Waste (SPW) for the Fabrication of Sustainable Bioplastic Film

et al. 2021

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“…Therefore, to meet the growing demands in automotive, transport, aerospace, marine, aeronautical, and missile technology; the size and morphology of the silicon phase must be refined and modified as the finer primary silicon crystals generally result in improved mechanical properties, such as toughness and ductility. Refinement can be achieved by controlling the nucleation and growth of the silicon phase via different chemical [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], mechanical [19][20][21][22], and thermal methods [23][24][25]. The chemical modification involves the addition of some modifier elements, in trace levels like Na [3][4][5], Sr [6], and rare earth elements [7].…”

Section: Introductionmentioning

confidence: 99%

Microstructural evolution and hardness of rapidly solidified hypereutectic Al-Si surface layers by laser remelting

Abboud

Kayitmazbatir

2022

Advances in Materials and Processing Technologies

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A laser rapid solidification technique was employed to remelt and refine the microstructure of Al-25wt.%Si and Al-30wt.%Si alloyed layers produced by laser melting. The microstructure of the as-fabricated Al-Si layers consisted of irregular polygonal primary Si crystals of size 5 to 7 µm, fine α-Al dendrites, and Al-Si eutectic. Laser rapid remelting results showed a significant refinement of all the solidified phases with increasing scan speed and decreasing laser power. At the lowest laser power (800W), the sizes of the primary Si crystals were reduced to a sub-micron level and an interwoven network of nano-sized eutectic colonies was obtained. The higher cooling rates, resulted in a reduction in the amount of the α-Al phase especially those surrounding the primary Si, thereby stimulating the eutectic Si fibers to grow from the pre-existing primary Si crystals and increased the proportion of the fibrous eutectic. Transmission electron microscopy revealed fibrous eutectic, which was internally nano-twinned, with a diameter approaching as low as 10-15 nm for the highest cooling rate. The hardness measured by nanoindentation of the eutectic in the remelted Al-25wt.%Si layer increased with decreasing the eutectic spacing (ʎ) reaching a maximum value of 3.15GPa.

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“…The advanced material of Si p /Al MMCs has characteristics such as a low coefficient of thermal expansion, low density, high thermal conductivity, good thermo-mechanical stability and is compatible with microelectronic assembly technology, etc. [11][12][13][14]. Due to the homogeneous distribution of Si particles in composites, components made from Si p /Al MMCs are nearly isotropic and readily formable [15,16].…”

Section: Introductionmentioning

confidence: 99%

Joining of Silicon Particle-Reinforced Aluminum Matrix Composites to Kovar Alloys Using Active Melt-Spun Ribbons in Vacuum Conditions

Gao

Yang

et al. 2020

Materials

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The vacuum brazing of dissimilar electronic packaging materials has been investigated. In this research, this applies silicon particle-reinforced aluminum matrix composites (Sip/Al MMCs) to Kovar alloys. Active melt-spun ribbons were employed as brazing filler metals under different joining temperatures and times. The results showed that the maximum joint shear strength of 96.62 MPa was achieved when the joint was made using Al-7.5Si-23.0Cu-2.0Ni-1.0Ti as the brazing filler metal at 580 °C for 30 min. X-ray diffraction (XRD) analysis of the joint indicated that the main phases were composed of Al, Si and intermetallics, including CuAl, TiFeSi, TiNiSi and Al3Ti. When the brazing temperature ranged from 570 °C to 590 °C, the leakage rate of joints remained at 10−8 Pa·m3/s or better. When the joint was made using Al-7.5Si-23.0Cu-2.0Ni-2.5Ti as the brazing filler metal at 580 °C for 30 min, the higher level of Ti content in the brazing filler metal resulted in the formation of a flake-like Ti(AlSi)3 intermetallic phase with an average size of 7 µm at the interface between the brazing seam and Sip/Al MMCs. The joint fracture was generally in the form of quasi-cleavage fracture, which primarily occurred at the interface between the filler metal and the Sip/Al MMCs. The micro-crack propagated not only Ti(AlSi)3, but also the Si particles in the substrate.

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Evolution of solidification structures and mechanical properties of high-Si Al alloys under permanent magnetic stirring

Cited by 33 publications

References 32 publications

Rapid Ultrasound-Assisted Starch Extraction from Sago Pith Waste (SPW) for the Fabrication of Sustainable Bioplastic Film

Rapid Ultrasound-Assisted Starch Extraction from Sago Pith Waste (SPW) for the Fabrication of Sustainable Bioplastic Film

Microstructural evolution and hardness of rapidly solidified hypereutectic Al-Si surface layers by laser remelting

Joining of Silicon Particle-Reinforced Aluminum Matrix Composites to Kovar Alloys Using Active Melt-Spun Ribbons in Vacuum Conditions

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