Authors: L Zhang D G Eskin L Katgerman
Publish Date: 2011/08/01
Volume: 46, Issue: 15, Pages: 5252-5259
Abstract
Ultrasonic melt treatment UST is known to induce grain refining in aluminum alloys Previous studies have clearly shown that in Al–Zr–Ti alloys the primary Al3Zr intermetallics were dramatically refined by cavitationassisted fragmentation and a good refinement effect was achieved In this article Al–Ti Al–Ti–Zr alloys and some commercial aluminum alloys are used to analyze the effect of UST on primary intermetallics and grain refinement The addition of a small amount of Al–3Ti–B master alloy is also studied in order to compare with the addition of Ti and Zr in commercial aluminum alloys Experimental results show that the ultrasonic grain refining effect is not only related to the size of particles which are refined and/or dispersed by UST but also related to an undercooling available for activation of these particles in the solidification process Athermal heterogeneous nucleation theory is considered to explain the effect of size and distribution of substrate particles on the grain structure with different undercoolings The distribution of primary particle sizes results in the distribution of required undercoolings Grain refining occurs when the undercooling is large enough to activate the refined primary intermetallics or dispersed inoculantsThe Authors would like to acknowledge the support of Materials innovation institute for the part of this study Cooperation with Dr TV Atamanenko is especially appreciated L Zhang would like to thank China Scholarship Council and Prof JS Zhang for providing the scholarship for the PhD study at TU DelftOpen AccessThis is an open access article distributed under the terms of the Creative Commons Attribution Noncommercial License https//doiorg/creativecommonsorg/licenses/bync/20 which permits any noncommercial use distribution and reproduction in any medium provided the original authors and source are credited
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