Influence of Semi-Solid Casting and Equal Channel Pressing on Microstructure of a Hypoeutectic Al-Si Alloy

The aim of this work was to develop understanding of microstructural evolution of the alloy casted in semi-solid condition using a cooling slope and conventional casting followed by ECAP in a 120odie. Feed materials were prepared by cooling slope casting and conventional casting for ECAP process. The microstructures and Vickers hardness of the worked materials extruded by two routes (A and BC) were evaluated. The primary α-Al phase tends to be elongated after processing by route A. However, its morphology was similar in nature to the microstructure of the as-cast sample after processing by route BC. The Si particles become fragmented during ECAP processing and are more nearly globular in shape and uniform in size than in the as-cast sample. The microstructure of the semi-solid cast ECAPed samples was more homogenous than that of the conventional cast ECAPed sample followed by ECAP for both routes. The hardness of semi-solid cast ECAP samples was also higher than that of conventional cast ECAPed samples for both routes.

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Formation of Globular Microstructure in A380 Aluminum Alloy by Cooling Slope Casting

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.264-265.272 ◽

2011 ◽

Vol 264-265 ◽

pp. 272-277 ◽

Cited By ~ 6

Author(s):

Nurşen Saklakoğlu ◽

S. Gencalp ◽

Şefika Kasman ◽

İ.E. Saklakoğlu

Keyword(s):

Aluminum Alloy ◽

Slope Angle ◽

Casting Process ◽

Solid Particles ◽

Inclined Plate ◽

Pouring Temperature ◽

Cooling Slope ◽

Semi Solid ◽

Cooling Slope Casting ◽

The Many

Thixoforming and related semi-solid processing (SSP) methods require thixotropic materials. One of the many SSP techniques is the cooling slope (CS) casting process, which is simple and has minimal equipment requirements, and which is able to produce feedstock materials for semisolid processing. When the feedstock is reheated to the semisolid temperature range, non-dendritic, spheroidal solid particles in a liquid matrix suitable for thixoforming are obtained. In this study, equipment for the CS technique was first established, and then the effects of the pouring temperature and inclined slope angle on the microstructures of A380 aluminum alloy (ISOAlSi8Cu3Fe) were studied. Optimum parameters for thixoforming experiments were selected, and it was found that the microstructure produced by the inclined plate depended on its angle and the pouring temperature.

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Microstructural Evaluation of Semi-Solid and Thixoformed Parts of LM28 Aluminum Alloy

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.192-193.136 ◽

2012 ◽

Vol 192-193 ◽

pp. 136-141

Author(s):

S.G. Shabestari ◽

P. Ghaemmaghami ◽

H. Saghafian ◽

A. Osanlo

Keyword(s):

Mechanical Properties ◽

Morphological Changes ◽

Physical And Mechanical Properties ◽

Primary Silicon ◽

Optical Microscope ◽

Globular Structure ◽

Cooling Slope ◽

The Matrix ◽

Semi Solid ◽

Cooling Slope Casting

Attractive physical and mechanical properties of aluminum alloys make them very interesting for the automotive industry. The commercial way for manufacturing LM28 alloy is die-casting, but this process encounters several problems such as shrinkage and gas porosities. Their good mechanical properties and high resistance to wear are because of the presence of hard primary silicon particles distributed in the matrix. Therefore, the size and morphology of primary silicon and also the structure of α-Al particles in hypereutectic Al–Si alloys influence the mechanical properties of the alloys. In this research, a new process of manufacturing of this alloy has been developed using LM28 feedstock produced through cooling slope casting. The feedstocks produced via cooling slope casting had a partial globular structure that contained globules, rosettes and dendrites of α-Al. These feedstocks were thixoformed under three different pressures. The primary dendrites and rosettes changed to globular structure. The microstructure of thixoformed parts contained α-Al globules, small primary Si particles dispersed between these globules, and Al-Si eutectic phase. The mechanism of the formation of α-Al globules by this process was explained. Microstructures of as cast specimens, feedstocks produced via cooling slope, specimens that were heat treated in the semi-solid temperature and thixoformed specimens were studied with optical microscope and image analysis. The morphological changes during these processes were interpreted.

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Microstructural Evaluation and Corrosion Resistance of Semisolid Cast A356 Alloy Processed by Equal Channel Angular Pressing

Metals ◽

10.3390/met9030303 ◽

2019 ◽

Vol 9 (3) ◽

pp. 303 ◽

Cited By ~ 3

Author(s):

Mohamed Gebril ◽

Mohd Omar ◽

Intan Mohamed ◽

Norinsan Othman

Keyword(s):

Corrosion Resistance ◽

Equal Channel Angular Pressing ◽

Cast Alloy ◽

A356 Alloy ◽

Cooling Slope ◽

Angular Pressing ◽

Ecap Process ◽

Heat Treated ◽

Microstructural Evaluation ◽

Cooling Slope Casting

As-cast and semisolid casting using a cooling slope A356 alloy were processed by equal channel angular pressing (ECAP) for Si and grain refinement. The ECAP was conducted at room temperature in a mold, with a channel angle of 120°, and this resulted in a significant size reduction of grain and Si particles from 170.5 and 4.22 to 23.12 and 0.71 µm, respectively, after six passes of heat-treated cooling slope casting, using the ECAP process. The hardness increased with ECAP processing, from 61 HV, for the as-cast alloy, to 134 Hv, after six passes of heat-treated cooling slope casting. The corrosion resistance of the alloy improved, from 0.042 to 0.0012 mmy−1, after the ECAP process. In this work both the strength and corrosion resistance of the ECAPed A356 alloys were improved with the application of the cooling slope process than without (i.e., from the as-cast condition).

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A Taguchi Optimization of Cooling Slope Casting Process Parameters for Production of Semi-solid A356 Alloy and A356-5TiB2 in-situ Composite Feedstock

Procedia Materials Science ◽

10.1016/j.mspro.2014.07.262 ◽

2014 ◽

Vol 5 ◽

pp. 232-241 ◽

Cited By ~ 19

Author(s):

S. Deepak kumar ◽

Pandu R. Vundavilli ◽

Sisir Mantry ◽

A. Mandal ◽

M. Chakraborty

Keyword(s):

Process Parameters ◽

A356 Alloy ◽

Casting Process ◽

Taguchi Optimization ◽

In Situ Composite ◽

Cooling Slope ◽

Semi Solid ◽

Cooling Slope Casting

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Preparation of Globular Microstructure Aluminum Alloy Using Cooling Slope Casting as Feed Material for Equal Channel Pressing Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1024.247 ◽

2014 ◽

Vol 1024 ◽

pp. 247-250 ◽

Cited By ~ 1

Author(s):

Nguyen Van Thuong ◽

Zuhailawati Hussain ◽

Anasyida Abu Seman ◽

T.D. Huy

Keyword(s):

Aluminum Alloy ◽

Mild Steel ◽

Casting Process ◽

Pouring Temperature ◽

Feed Material ◽

Globular Microstructure ◽

Cooling Slope ◽

Semi Solid ◽

Cooling Slope Casting ◽

Steel Mould

Equal channel angular pressing (ECAP) could be used to achieve ultra fine grains in bulk aluminum alloy through severe plastic deformation. Typically a feed material of as-cast aluminum alloys is used with a typical hypoeutectic solidification structure, consisting of primary aluminum dendrites and interdendritic network of lamellar eutectic silicon. On the other hand, semi-solid metal casting provides non-dendritic and globular microstructure which is one of a considerable factor in obtaining homogenous microstructure after ECAP. This work is an attempt to produce aluminum alloy with globular microstructure using cooling slope semi-solid casting process which is believed suitable as a feedstock for ECAP. The aim of this work described in this paper was to understand of microstructural evolution of aluminum structure during cooling slope casting process. Two experiments were carried out. A sample was casted via a cooling slope into a vertical cold mild steel mould at pouring temperature of 640°C. Cooling slope length of 250 mm, slope temperature of room temperature and tilt angle of 60owas applied. Another sample was casted directly into a vertical cold mild steel mould at pouring temperature of 640°C. The primary α-Al phases in the sample that casted without cooling slope was mostly in dendritic throughout the section of sample whilst the primary α-Al phases transformed completely into non-dendritic in the sample that was casted via the cooling slope. Therefore, the transformation is believed resulted from the effect of cooling slope

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Microstructural Evolution of ETIAL 160 Aluminium Alloy Feedstock Produced by Cooling Slope Casting

Solid State Phenomena - Semi-Solid Processing of Alloys and Composites X ◽

10.4028/3-908451-59-0.575 ◽

2008 ◽

pp. 575-580

Author(s):

Nurşen Saklakoğlu ◽

Yücel Birol ◽

Şefika Kasman

Keyword(s):

Aluminium Alloy ◽

Microstructural Evolution ◽

Cooling Slope ◽

Cooling Slope Casting

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Production of semi-solid feedstock of A356 alloy and A356-5TiB2 in-situ composite by cooling slope casting

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/75/1/012026 ◽

2015 ◽

Vol 75 ◽

pp. 012026

Author(s):

S Deepak Kumar ◽

Mihira Acharya ◽

A Mandal ◽

M Chakraborty

Keyword(s):

A356 Alloy ◽

In Situ Composite ◽

Cooling Slope ◽

Semi Solid ◽

Cooling Slope Casting

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Evaluation of Strip Rolling Directly from the Semi-Solid State

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.116-117.433 ◽

2006 ◽

Vol 116-117 ◽

pp. 433-436 ◽

Cited By ~ 3

Author(s):

Antonio de Pádua Lima Filho ◽

Márcio Iuji Yamasaki

Keyword(s):

Solid State ◽

Cooling System ◽

Solid Alloy ◽

Strip Rolling ◽

Tin Alloys ◽

Cooling Slope ◽

Quality Issue ◽

Lower Roller ◽

Semi Solid ◽

Strip Quality

The aim of this work is to study the solidification conditions necessary to produce good quality/low defect metal alloy strip when thixorolling directly from the semi-solid state. To facilitate the study lead/tin alloys were chosen for their relatively low operating temperature. The objective is to extrapolate these findings to the higher temperature aluminium alloys. Three alloys (70%Pb- 30%Sn, 60%Pb-40%Sn, 50%Pb-50%wtSn) were used particularly to study the influence of the solidification interval. The equipment consists of a two roll mill arranged as an upper and lower roller, where both rollers are driven at a controlled speed. The lower roller is fed with semi solid alloy through a ceramic nozzle attached to the lower end of a cooling slope. Several types of nozzle and their position at the roller were tested. This produced different solidifications and consequently different finished strip. The alloys were first cast and then poured onto the cooling slope through a tundish in order to create a continuous laminar flow of slurry and uniformity of metal strip quality. The pouring was tested at different positions along the slope. The cooling slope was coated with colloidal graphite to promote a smooth slurry flow and avoid the problem of adherence and premature solidification. The metallic slurry not only cools along the slope but is also initially super-cooled to a mush by the lower roller whilst at room temperatures, thus enabling thixorolling. It was also found that the nozzle position could be adjusted to enable the upper roller to also contribute to the solidification of the metallic slurry. However the rollers and the cooling slope naturally heat up. Temperature distribution in these zones was analysed by means of three thermocouples positioned along the cooling slope and a fourth in the base of the semi solid pool within the nozzle. The objective being to design an optimum pouring and cooling system. The formed strip was cooled down to room temperature with a shower of water. Microstructures of the thixorolling process were analysed. The differences in solidification conditions resulted in differing qualities of finished strip and corresponding defect types, all of which are a serious quality issue for the rolled product.

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