| About this Abstract |
| Meeting |
Materials Science & Technology 2020
|
| Symposium
|
Thermodynamic Properties, Structure and Phase Stabilities of Special Alloys
|
| Presentation Title |
Thermal Decomposition of Quasicrystals in Powder-processed Icosahedral-Phase-strengthened Aluminum Alloys |
| Author(s) |
Hannah R. Leonard, Sarshad Rommel, Mingxuan Li, Thomas Watson, Tod Policandriotes, Mark Aindow |
| On-Site Speaker (Planned) |
Hannah R. Leonard |
| Abstract Scope |
Recently, we have developed a series of Al-Cr-Mn-Co-Zr alloys that exhibit a nano-composite FCC Al plus I-phase microstructure in gas-atomized powders. The I-phase dispersoids exhibited a variation in microstructures and distribution that depended on the powder particle size (hence cooling rate) and the alloy composition. This microstructure is retained during consolidation of the powder to form bulk materials or cold-sprayed coatings, and the materials exhibit remarkable mechanical properties. Here we report a study on the thermal stability and decomposition of the I-phase in this Al alloy. A series of isothermal heat treatments were performed to determine the conditions under which the quasicrystalline phase decomposes. In-situ TEM heating experiments were performed with a MEMS-based heating holder on specimens prepared using a FIB technique from individual powder particles and from consolidated material. Experiments were conducted to investigate the transformation mechanisms for each of the different microstructures. |