Evolution of the As‐Cast Grain Microstructure of an Ultrasonically Treated Al–2Cu Alloy. Issue 11 (12th August 2018)

• Record Type: Journal Article
• Authors: Wang, Gui; Croaker, Paul; Dargusch, Matthew; McGuckin, Damian; StJohn, David
• Is Part Of: Advanced engineering materials. Volume 20:Issue 11(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-08-12
• Subjects: acoustic streaming -- cellular automation finite element -- solidification -- ultrasonic treatment; Materials -- Periodicals; 620.11
• DOI: 10.1002/adem.201800521
• Languages: English
• ISSNs: 1438-1656

Abstract

Abstract : The evolution of the grain structure of an Al–2Cu alloy is investigated numerically during its solidification while being subjected to ultrasonic treatment. A CAFE (Cellular Automation Finite Element) model coupling fluid flow, heat transfer, nucleation, and grain growth is developed and validated by comparing the results of both numerical simulations and physical experiments. The model successfully describes hydrodynamic fields generated by ultrasonic treatment and their influence on microstructural evolution. This validated model is then used to study the influence of the duration of ultrasonic treatment on temperature distribution and grain structure. A predominantly equiaxed grain structure developed due to the low temperature gradient throughout the melt is a result of the enhanced convection. These results highlight the critical role played by the convection induced by acoustic streaming during casting, that is, facilitating nucleation and grain growth. Abstract : A Cellular‐Automata/Finite‐Element (CAFE) numerical model describing the hydrodynamic fields generated by ultrasonic treatment (UST) and their influence on microstructural evolution of an Al–2Cu alloy is used to investigate the influence of the duration of ultrasonic treatment on temperature distribution and grain structure. The results show that the convection induced by acoustic streaming inherent in UST plays a critical role in facilitating nucleation and growth of grains.