| About this Abstract |
| Meeting |
Materials Science & Technology 2020
|
| Symposium
|
Microstructure and Physical Property Optimization in High Entropy Alloys
|
| Presentation Title |
Short-range Atomic Order Drives Exceptional Mechanical Properties of Multi-principal Element Alloys |
| Author(s) |
Sezer Picak, Prashant Singh, Yuriy Chumlyakov, Duane D Johnson, Raymundo Arroyave, Ibrahim Karaman |
| On-Site Speaker (Planned) |
Sezer Picak |
| Abstract Scope |
High and medium entropy alloys (HEAs/MEAs) are a new class of multi-principal element alloy (MPEA) systems with unique mechanical and functional behavior. Here, we reveal, both theoretically and experimentally, the complex deformation mechanisms responsible for the exceptional mechanical response of FeMnCoCrNi, Fe40Mn40Co10Cr10 and NiCoCr, which are model MPEAs. Our first-principles thermodynamic analysis unequivocally proves the existence of a short-range order (SRO). Although the existence of SRO in MPEAs has been correlated with planar-slip in the literature, our theoretical and experimental approaches show that SRO is responsible for the simultaneous deformation twinning-induced-plasticity and martensitic transformation-induced plasticity (TWIP/TRIP), and thus, is responsible for unusual deformation in these MPEAs. The bulk single-crystal experiments establish the role of SRO in the simultaneous observation of TWIP/TRIP, with nanometer range twin and martensite thicknesses. These concurrent strengthening mechanisms triggered by SRO point towards strategies to further improve or discover new classes of MPEAs with tunable properties. |