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.

Thixocasting of Al-7%Si Alloy Billets Prepared by Ultrasonic Treatment

2016 ◽  
Vol 256 ◽  
pp. 276-281
Author(s):  
Waleed Khalifa ◽  
Yoshiki Tsunekawa
Keyword(s):  
Ultrasonic Treatment ◽  
Melt Treatment ◽  
Intermetallic Particles ◽  
Eutectic Si ◽  
Feedstock Production ◽  
Dendritic Microstructures ◽  
Ultrasonic Melt Treatment ◽  
Highly Uniform

The feasibility of using the ultrasonic melt treatment to prepare billets for thixocasting process of hypoeutectic Al-7%Si alloys was studied in this paper. The work covered the billet preparation, soaking treatments and thixocasting process, with focus on the microstructural features in each case. The results showed that the use of ultrasonic treatment in billet preparation resulted in highly uniform, fine and non-dendritic microstructures. Billets with globule sizes as small as 58 µm, and roundness of more than 0.7 were obtained by ultrasonic melt treatment. Different soaking conditions before thixocasting were done and the optimum from which was the soaking for 5 min at 580°C, which resulted in thixocast parts with excellent combination of fine globules of 80 µm and roundness of 0.7 - 0.81. The eutectic Si, as well, was greatly refined by the ultrasonic thixocasting process. Furthermore, high-Fe ultrasonic treated billets, which were thixocasted successfully, exhibited Fe-intermetallic particles in highly desirable fine compacted form. These results reveal the feasibility and competence of UST as a potential route for feedstock production.

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.

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

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):  
Surface Roughness ◽  
Aluminum Alloy ◽  
Tribological Properties ◽  
Lower Surface ◽  
Test Method ◽  
Ring Test ◽  
7075 Aluminum Alloy ◽  
Melt Treatment ◽  
Ultrasonic Melt Treatment ◽  
Worn Surfaces

Abstract In this study, the tribological properties of 7075 aluminum alloy produced by ultrasonic melt treatment (UST) are investigated. Tribological properties of untreated and ultrasonically treated samples under dry and lubricated sliding conditions were analyzed experimentally by the block on ring test method. Worn surfaces of untreated and ultrasonically treated samples were scanned by 3D optical profilometer and analyzed to search out wear characteristics in the material. Furthermore, microstructural examinations were conducted to investigate the beneficial effects of UST on the microstructural properties of the alloy using optical and scanning electron microscopy. According to the results obtained, UST refines the α-Al phase of the alloy and disperses precipitates to grain boundaries more uniformly. Also, hardness and density of the alloy increased through the effect of UST. Due to these favorable effects, the wear resistance of the alloy increased and the worn surfaces of the ultrasonically treated samples exhibited lower surface roughness according to 3D surface roughness measurements.

Effect of Ultrasonic Melt Treatment on Solidification Structure of Fe-36Ni Invar Alloy

2013 ◽  
Vol 32 (5) ◽  
pp. 459-465 ◽  
Author(s):  
Hong-bing Peng ◽  
Wei-qing Chen ◽  
Yan-chong Yu ◽  
Hong-guang Zheng
Keyword(s):  
Ultrasonic Treatment ◽  
Solidification Process ◽  
Ultrasonic Cavitation ◽  
Solidification Structure ◽  
Invar Alloy ◽  
Pouring Temperature ◽  
Melt Treatment ◽  
Different Temperatures ◽  
Ultrasonic Melt Treatment ◽  
Average Size

AbstractThe effect of ultrasonic treatment on the solidification structure of Fe-36Ni invar alloy was investigated. The experiment results showed that the ultrasonic treatment before its solidification had no significant effect on the solidification structure. However, when ultrasonic was inputted into the molten alloy during its solidification process, the primary dendrites were broken up into lots of fragments and solidification structure was refined significantly. When ultrasonic treatment was applied in the melt doped with yttrium before its solidification, ultrasonic cavitation could break up precipitates into many small ones, which could refine its solidification structure as nucleation cores. In samples containing yttrium treated by ultrasonic at 1753 K, the number of the precipitates was 623/mm2 and its average size was 2.18 µm; while at 1803 K, they were 604/mm2 and 2.34 µm respectively. The ultrasonic cavitation had a similar effect at two different temperatures. The solidification structure refined greatly at 1753 K was due to its low pouring temperature.

scholarly journals Microstructure and Mechanical Property of Al6Si2Cu Alloy Subjected to Double-Solution Heat Treatment

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 18
Author(s):  
Seongbin An ◽  
Minsuk Kim ◽  
Chaeeul Huh ◽  
Chungseok Kim
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aluminum Alloy ◽  
Intermetallic Phase ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Solution Temperature ◽  
Eutectic Si ◽  
Equilibrium Phases ◽  
Al Matrix

This study aims to develop the mechanical properties of the Al6Si2Cu aluminum alloy through the double-solution treatment. In addition to the Al matrix, large amounts of coarse eutectic Si, Al2Cu intermetallic, and Fe-rich phases were generated through thermo-calc simulation in agreement with the equilibrium phases. The eutectic Si phase is fragmented and spheroidized by the solution treatment as the heat treatment temperature and time increase. The Al2Cu intermetallic phase is dissolved into the Al matrix, resulting in an increase in both strength and elongation. The second-step solution temperature at 525 °C should be an optimum condition for enhancing the mechanical properties of the Al6Si2Cu aluminum alloy.

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