• 한국주조공학회지
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• 제32권6호
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• pp.269-275
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• 2012

Al-Mg-Si/Al hybrid alloy was prepared by Duo-casting and the mechanical behavior was evaluated based on their microstructure and mechanical properties. The hybrid aluminum alloy included the Al-Mg-Si alloy with fine eutectic structure, pure Al with the columnar and equiaxed crystals, and the macro-interface existing between Al-Mg-Si alloy and pure Al. The growth of columnar grains in pure Al occurred from the macro-interface. The tensile strength, 0.2% proof stress and bending strength of the hybrid aluminum alloy were almost similar to those of pure Al, and the elongation was much higher than the Al-Mg-Si alloy. The fracture of the hybrid alloy took place in pure Al side, indicating that the macro-interface was well bonded and the mechanical behavior strongly depends on the limited deformation in pure Al side.

• 한국재료학회지
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• 제28권9호
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• pp.499-505
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• 2018

This investigates the microstructure and mechanical properties of Al hybrid material prepared by electromagnetic duo-casting to determine the effect of heat treatment. The hybrid material is composed of an Al-Mg-Si alloy, pure Al and the interface between the Al-Mg-Si alloy and pure Al. It is heat-treated at 373, 573 and 773K for 1h and T6 treated (solution treatment at 773K for 1h and aging at 433K for 5h). As the temperature increases, the grain size of the Al-Mg-Si alloy in the hybrid material increases. The grain size of the T6 treated Al-Mg-Si alloy is similar to that of one heat-treated at 773K for 1h. The interface region where the micro-hardness becomes large from the pure Al to the Al-Mg-Si alloy widens with an increasing heat temperature. The hybrid material with a macro-interface parallel to the tensile direction experiences increased tensile strength, 0.2 % proof stress and the decreased elongation after T6 heat treatment. On the other hand, in the vertical direction to the tensile direction, there is no great difference with heat treatment. The bending strength of the hybrid material with a long macro-interface to the bending direction is higher than that with a short macro-interface, which is improved by heat treatment. The hybrid material with a long macro-interface to the bending direction is fractured by cracking through the eutectic structure in the Al-Mg-Si alloy. However, in the hybrid material with a short macro-interface, the bending deformation is observed only in the limited pure Al.

• 한국재료학회지
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• 제30권3호
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• pp.111-116
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• 2020

Two different casting speeds of 60 and 80mm/min are adopted to determine the effect of casting speed on the microstructure and mechanical properties of Al-Mg-Si/Al hybrid material prepared by duo-casting. The obtained hybrid material has a uniform and straight macro-interface between the pure Al side and the Al-Mg-Si alloy side at both casting speeds. When the casting speed is increased to 80mm/min, the size of primary α phases in Al-Mg-Si alloy decreases, without change of shape. Although the Al-Mg-Si alloy produced at higher casting speed of 80mm/min shows much higher ultimate tensile strength (UTS) and 0.2 % proof stress and lower elongation, along with higher bending strength compared to the case of the 60mm/min in casting speed, the tensile properties and bending strength of the hybrid material, which are similar to those of pure Al, are the same regardless of the increase of casting speed. Despite the different casting speeds, deformation and fracturing in hybrid materials are observed only on the pure Al side. This indicates that the macro-interface is well-bonded, allowing it to endure tensile and bending deformation in all hybrid materials.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.143-146
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• 2002

Mg alloy is the lightest material of structural materials and is noticed for lightweight automotive parts because of excellent castability, superior ductility and damping capacity than Al alloy. But Mg Alloy is poor corrosion resistance and high temperature creep properties. In this study, Mg Matrix Composites were fabricated by squeeze casting method to improve high temperature creep properties and damping capacity. Hybrid Mg composites reinforced with Alborex, graphite particle, and SiCp was improved creep properties and damping capacity compared with Mg alloy. Compared to the length ($9\mu\textrm{m}, 27\mu\textrm{m}, 45\mu\textrm{m} etc.$), Hybrid Mg composites reinforced with SiCp, one of the most superior of the length and Alborex were more superior than those reinforced with graphite particle and Alborex in mechanical properties, creep characteristics, and damping capacity, etc.

• 한국주조공학회지
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• 제23권1호
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• pp.30-39
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• 2003

Porous hybrid preforms were fabricated by reactive sintering using the compacts consisting of SiC particles, Fe and Al powders. Squeeze casting processing was employed to produce the composite in which the matrix phase is Al-Si7Mg. The microstructural change and wear resistance of the composites were investigated in terms of an amount of SiC particles. The wear loss was increased with increasing the contact pressure in the alloy containing SiC particles coated with Cu. The most drastic change was found to the specimen tested at 2.5 MPa of contact pressure. Concerning the alloys containing SiC particles coated with Ni-P, a drastic increase in the wear loss exhibited at 2 MPa of contact pressure in those alloys containing 4 and 8 wt. % of SiC particles coated with Ni-P. In the alloy containing 16 wt. % a proportional increase in wear loss was observed to the change of contact pressure. With respecting to the sliding velocity, the wear loss of the alloy containing SiC particles coated with Cu increased at the initial stage of wear process and then decreased. Similar result was found in the alloys containing SiC particles coated with Ni-P. On the basis of the present results obtained, it was found that wear resistance of the alloys tested was improved to show in the order of the alloy reinforced by coated SiC particles > by uncoated SiC particles > by intermetallic compound without SiC particles.