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 An investigation was carried out on the grain refinement of molten AA5754 Aluminum alloy through intensive shearing. The results show intensive shearing via cavitation decreases the grain size significantly. The above hypothesis for structure refinement was evaluated and an experiment was performed to ensure the creditability of this assumption. Finally, it…
Writing By Reza Haghayeghi : Abstract : Conventional Grain Refinement is Performed Through the addition of chemical refiners. However, This article proposes physical refinement as an alternative method for producing fine grain size. Two methods of physical refinement are examined and evaluated, namely Melt Conditioning by Advanced Shear Technology (MCAST) and the use of an…
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…
Writing By Reza Haghayeghi: The influence of intensive shearing above liquidus on the Solidification Process, microstructural evolution and its effect on the final Microstructure for the Al–10 wt% Mg alloy were investigated and discussed thor- oughly. The effect of shearing was explored and was compared with non-sheared samples. The effects of relaxation (holding melt after…
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…