Effect of Reheating to the Semisolid State on the Microstructure of the A356 Aluminum Alloy Produced by Ultrasonic Melt-Treatment

2008 ◽  
pp. 499-504
Author(s):  
W. Khalifa ◽  
Yoshiki Tsunekawa ◽  
Masahiro Okumiya
Keyword(s):  
Aluminum Alloy ◽  
A356 Aluminum Alloy ◽  
Semisolid State ◽  
Melt Treatment ◽  
A356 Aluminum ◽  
Ultrasonic Melt Treatment

scholarly journals Effect of Reheating to the Semisolid State on the Microstructure of the A356 Aluminum Alloy Produced by Ultrasonic Melt-Treatment

2008 ◽  
Vol 141-143 ◽  
pp. 499-504 ◽  
Author(s):  
W. Khalifa ◽  
Yoshiki Tsunekawa ◽  
Masahiro Okumiya
Keyword(s):  
Growth Rate ◽  
Aluminum Alloy ◽  
Rate Constants ◽  
Ostwald Ripening ◽  
A356 Aluminum Alloy ◽  
Semisolid State ◽  
Melt Treatment ◽  
A356 Aluminum ◽  
Ultrasonic Melt Treatment ◽  
Semi Solid

The effect of reheating to the semisolid state (soaking treatment) on the microstructure evolution of the A356 aluminum alloy prepared by ultrasonic melt treatment was studied in this paper. The results showed that in general the longer the soaking process the larger and the more round the grains obtained. Higher roundness occurs at shorter soaking times in the fine-grained ascast samples, and at longer times in the inhomogeneous or the coarser-grained as-cast structures. The optimum thixotropic condition (high roundness, 0.72, and small globule sizes < 90 μm) are achieved after 5 min. soaking in the samples treated by UST at 623 and 620oC, which is the typical soaking time dictated by the industrial practice in SSM. The amount of entrapped eutectic as observed after soaking treatments is uniquely very small, suggesting that the UST-treated ingots will have better formability in the semisolid state. The growth rate constants are substantially low: in the order of 479-748 μm3/s. These growth rate constants are much lower than those reported for MHDcast A356 ingots. The growth rates of the samples produced by UST in the liquid state (i.e., 626, 623 and 620oC. Note that liquidus temperature is 619oC) are lower than those of the samples treated in the semi-solid temperatures, i.e., 617 and 614oC. The Ostwald ripening is most likely the dominant growth mechanism in the UST-treated samples during the soaking treatments. These results reveal the feasibility and competence of UST as a potential route for thixotropic feedstock production.

scholarly journals Structure and mechanical properties of A356-C alloys

2018 ◽  
Vol 243 ◽  
pp. 00024
Author(s):  
Marina Khmeleva ◽  
Anton Khrustalev ◽  
Alexander Vorozhtsov
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Mechanical Characteristics ◽  
Casting Alloy ◽  
A356 Aluminum Alloy ◽  
Mechanical Mixing ◽  
Alloy Structure ◽  
Melt Treatment ◽  
Mechanical Tensile ◽  
A356 Aluminum

The paper deals with influence of mechanical mixing and vibration treatment on the structure and mechanical characteristics of the aluminum alloy containing ≤ 1 wt.% of nanodiamonds (A356-C). The alloy was obtained from industrial A356 Al-Si casting alloy by means of an integrated effect of mechanical mixing and vibration. It has been shown that the introduction of nanodiamond particles contributes to improving the alloy structure and increasing its mechanical tensile properties. The structure of the A356 aluminum alloy has been refined with introduction of 0.2 wt% nanodiamonds and application of vibration melt treatment. The introduction of nanodiamonds into the melt and the vibration melt treatment enable one to increase the yield strength and tensile strength of the A356 aluminum alloy without any change in ductility.

Ultrasonic Rheo-Diecasting of A383 Aluminum Alloy

2016 ◽  
Vol 256 ◽  
pp. 282-287 ◽  
Author(s):  
Waleed Khalifa ◽  
Yoshiki Tsunekawa ◽  
Shimaa El-Hadad
Keyword(s):  
Aluminum Alloy ◽  
Treatment Temperature ◽  
Shot Sleeve ◽  
Semisolid State ◽  
Melt Treatment ◽  
Intermetallic Particles ◽  
Eutectic Si ◽  
Different Temperatures ◽  
Ultrasonic Melt Treatment ◽  
Fe Intermetallics

In this study, un-refined A383 aluminum alloy was cast at different temperatures using ultrasonic melt treatment. The liquid alloy was treated by ultrasonic vibrations in the crucible and/or in the shot sleeve of a pressure diecasting machine. The treatment temperature extended to the semisolid temperature range. The UST melt could be injected into the die cavity while being in the semisolid state which is known as rheodiecasting. The results showed that ultrasonic treatment resulted in finer microstructure, globular Fe-intermetallic particles and partially modified eutectic Si. For samples solidified in shot sleeve: Fe-intermetallics become compacted with UST at all positions of ingot. Si particles are compacted in less acicular form near to horn and acicular at other positions. For the rheo-diecasting experiments, with UST treatment in the crucible and die casting, at 600-588 C and 588-578C, Fe-intermetallics were observed in compact form, and Si particles were highly modified.

Effect of ultrasonic melt treatment on the tribological behavior of 7075 aluminum alloy

2020 ◽  
Vol 62 (12) ◽  
pp. 1243-1250
Author(s):  
Fahri Vatansever ◽  
Alpay Tamer Erturk ◽  
Erol Feyzullahoglu
Keyword(s):  
Aluminum Alloy ◽  
Tribological Behavior ◽  
7075 Aluminum Alloy ◽  
Melt Treatment ◽  
Ultrasonic Melt Treatment
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