Grain Refinement Efficiency of a New Oxide-Containing Master Alloy for Aluminium Casting Alloys

Abstract

In this study, grain refinement efficiency of a new oxide-containing master alloy was demonstrated on an A357 alloy. The grain size of the reference alloy was reduced by 50-60% with the addition of the master alloy and introduction of ultrasonic cavitation. A higher addition of master alloy was found to be not benificial in further reducing the grain size.

Development of New Oxide Based Master Alloys and their Grain Refinement Potency in Aluminium Alloys

“…The grain size was reduced for reference alloys from 900 µm (Fig 4 The initial grain size was noticed to be ~900 µm. The grain size was reduced appreciably with the addition of master alloys [15]. However, there was no more grain size reduction observed above 1.7 wt.% of MA addition.…”

Potential of an Al-Ti-MgAl2O4 Master Alloy and Ultrasonic Cavitation in the Grain Refinement of a Cast Aluminum Alloy

“…Recent work showed that ultrasonication was capable of dispersion of in situ MgAl 2 O 4 particulates in liquid metal, while manual or mechanical stirring apparently failed to distribute fine particles in the liquid metal. [14,21] The presence of free Ti in the master alloy adds to the grain-refining effect through growth restriction. This becomes evident if one compares the results reported on the grain refinement by a similar master alloy with spinel but without Ti [14] (Figure 16) with the results reported in this article.…”

“…[14,21] The presence of free Ti in the master alloy adds to the grain-refining effect through growth restriction. This becomes evident if one compares the results reported on the grain refinement by a similar master alloy with spinel but without Ti [14] (Figure 16) with the results reported in this article. For the reader's convenience, the data are summarized in Figure 17.…”

“…In recent times, interest has grown on using oxides such as Al 2 O 3 , MgAl 2 O 4 , and MgO as nucleation substrates in Al. [13][14][15] It is well known that these oxides are formed naturally on the aluminum melt surface as stable layers, being thermodynamically stable and having sufficiently good crystallographic match with solid aluminum to act as substrates for its nucleation. [13] Similarly, these oxides can be formed in situ as a reaction product of externally added oxide particles and liquid aluminum.…”

Structure–property analysis of in-situ Al–MgAl2O4 metal matrix composites synthesized using ultrasonic cavitation

“…G is the shear modulus, E m is the young modulus of matrix alloy, 68 GPa, is the Poisson's ratio, 0.33, b is the Burger's vector (0.286nm), is the dislocation density induced by CTE mismatch, which can be calculated by the equation [35] …”