Effect of conventional and rheocasting processes on microstructural characteristics of hypereutectic Al–Si–Cu–Mg alloy with variable Mg content

Enhancing Properties of Cast Al Alloys by Rheocasting and Nano-Dispersions

“…15) with the processing method developed in this work is obvious. Previous findings have found increased Si particles segregation due to rheo-casting [9] and were explained to be resulting from the shear forces during stirring while solidification occurs. Also an overall trend for size decrease was apparent in the studied samples except for the material containing 0.5% Al 2 O 3 &0.5% TiO 2 cast in semi-solid state which revealed a wide scatter in the silicon particles size, whilst the sample material 0.5% Al 2 O 3 &0.5% TiO 2 cast in liquid state has shown relatively higher content of refined primary silicon particles, though these results maybe an effect of non-homogeneous processing conditions, further study of the role of adding TiO 2 in liquid state should be investigated..…”

“…The morphology of the primary silicon in all the studied samples remains as polygonal except in the sample containing 1% Al 2 O 3 where little primary silicon particles in needle like shape were spotted (13 a). Moreover, it is shown from the micrograph (13 a) that the eutectic silicon has two morphologies, one is present in spaces between α-Al dendrite arms and it can be found to be fine, skeleton network with Chinese script morphology [9]; the second one can be found around the primary silicon particles and it is in the shape of flakes 13 b). Table (7) and Figure (14) show the influence of nanoparticles addition on some microstructure features namely; dendritic arm length, interdendritic arm spacing and interlamellar spacing in the eutectic silicon phase.…”

Rheo-Die-Casting of Al-Si-Mg Alloy and Al-Si-Mg/ SiCp Composites: Microstructure and Wear Behavior

“…In the RDC alloy, the Si particles are very fine and uniformly distributed throughout the sections. In contrast, the HPDC alloy showed both plate and needle-like Si particles, which promote brittleness 15 . This undesirable microstructure can be modified by the addition of modifying agent (either Na or Sr) during melting.…”

“…This value is related to low silicon content in the aluminium alloy. However, low silicon content leads to high viscosity values and is usually not suitable for good thixotropic behavior required for semisolid processing 15 . Birol 16 studied the microstructure of semi-solid processed A356 die-casting alloy and found that the solid fraction linearly increased in semi-solid temperature range.…”

Effect of SIMA Process on Microstructure and Wear Behavior of Al-Mg2Si-3% Ni Composite

“…Many advantages have been reported for this composite such as low density, suitable wear resistance and excellent cast ability and much lower costs of production [1][2][3][4] which are the reasons to choose this composite in industrial applications. Researchers attribute these advantages to the formation of Mg 2 Si intermetallic compound during solidification [5,6] which has a high melting point (1085 °C), very low density (1.99 × 10 3 kg/ m −3 ), high hardness (4.5 × 10 9 N m −2 ), a low thermal expansion coefficient (7.5 × 10 6 K −1 ) and a reasonably high elastic modulus (120 GPa) [1,5]. Although some similarities have been seen between Mg 2 Si and Si in terms of properties and solidification behavior [7,8], Al-Mg 2 Si composite has better mechanical properties compared with Al-Si composite [9].…”