About this Abstract |
Meeting |
MS&T22: Materials Science & Technology
|
Symposium
|
Additive Manufacturing of Metals: Microstructure, Properties and Alloy Development
|
Presentation Title |
The Role of Nucleation in Determining the Microstructure Development in Rapidly Solidified Alloys |
Author(s) |
Nima Najafizadeh, Yijia Gu |
On-Site Speaker (Planned) |
Nima Najafizadeh |
Abstract Scope |
It is established that rapid solidification processing of materials enables the formation of exotic non-equilibrium microstructures. However, the interrelationship between the processing parameters and the resulting microstructure is yet to be fully understood. In melt spinning and additive manufacturing of rapidly solidified alloys, two opposite morphology sequences have been observed. Despite having similar magnitudes of cooling rates, and both being categorized as the rapid solidification processes, melt spinning and additive manufacturing resulted in fine-to-coarse and coarse-to-fine microstructure transitions, respectively. The present work aims to use a phase-field model to investigate the microstructural evolution during these processes by taking different nucleation conditions and controlling mechanisms for growth into account. It is found that the onset of nucleation plays a critical role in the development of microstructures. The huge difference in undercooling between additive manufacturing and melt spinning is found to be the cause of the observed opposite sequence of morphologies. |