Write By Reza Haghayeghi : Enhanced refinement and modification via self-inoculation of Si phase in a Hyper eutectic aluminium alloy The alloy A390 was ultrasonically treated, and the resulting material was referred to as master alloy. The master alloy was added into a non-treated A390 melt over two different levels: 10 and 20% by volume in…
Write By Reza Haghayeghi : Abstract. Melt Conditioned Direct Chill (MC-DC) casting is a new development for producing high-quality billets and slabs. In the MC-DC process, liquid metal is continuously fed into a MCAST (melt conditioning by advanced shear technology) machine, where the liquid metal is subjected to high shear rate and high degree of turbulence provided by…
Write By Reza Haghayeghi : Abstract The influence of intensive shearing was studied at above liquidus temperature on solidification process of two common industrial aluminium alloys. The shearing effects on the final microstructure of AA5754 and AA7449 aluminium alloys were investigated. The result of shearing on the grain size was explored and compared with non-sheared…
Writing By Reza Haghayeghi There has been a great debate whether grain refinement is more effective when shearing above or below the liquidus. In this work, examination of the microstructural evolution in AA7075 alloy has been performed, after stirring above & below the liquidus. The results suggest that shearing above the liquidus is more effective….
Writing By Reza Haghayeghi Step-by-step in situ near-atomic-resolution observations were presented for initial crystallization or nucleation in a liquid Al-10Mg (wt%) alloy containing spinel (MgAl2O4) seeds. Ordering of Al atoms was observed in the alloy at the interface with spinel at the superheat of 73 _C or at the melt temperature of 680 _C, where…
Reza Haghayeghi Abstract: The effects of ultrasonic treatment (UT) and electromagnetic stirring (EMS) forces, individually and in combination, prior to high pressure die-casting of AA5754 alloy were assessed. The liquid of alloy was subjected to UT, EMS and the combined style and then transferred to the shot chamber. The grain size, mechanical properties, gas content…
Writing By Reza Haghayeghi : The effects of introducing ultrasonic vibrations prior to high pressure die casting have been experi- mentally investigated. Results suggest reductions of up to 73% in grain size and up to 5% on porosity levels due to cavitation, leading to enhanced structural performance. The typical values of ultimate tensile stress…
Writing By Reza Haghayeghi : Twin screw melt conditioners are used for mixing purposes and are mainly used for polymer processing. These conditioners (extruders) can be used for liquid metal processing in which liquid metal/slurry is subjected to high shear stress. This process results in grain refinement of structure. In this article, in a co-rotating twin…
Reza Haghayeghi Abstract: The effects of ultrasonic treatment (UT) and electromagnetic stirring (EMS) forces, Individually and in combination, Prior to high pressure die-casting of AA5754 alloy were assessed. The liquid of alloy was subjected to UT, EMS and the combined style and then transferred to the shot chamber. The grain size, Mechanical properties, Gas content…
© 2016 Elsevier Inc. All rights by Reza Haghayeghi In thixoforming processes control of the solid-to-liquid transition and grain size of the mush metal is essential. If eutectic melting is avoided, subsequent melting of the primary phase should be controllable. To achieve this, the sensitivity of the liquid fraction, dfL/dT, at the desired liquid fraction,…