|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Advances in Multi-Principal Elements Alloys X
||Mechanical properties of Ti20Zr20Nb25Ta25Al10 refractory high entropy superalloys in tension
||Sangjun Kim, Jon Ell, Qin Yu, Yang Yang, Andrew M. Minor, Eun Soo Park, Robert O. Ritchie
|On-Site Speaker (Planned)
Precipitate-hardened bcc refractory high-entropy superalloys (RHEAs) have been reported to exhibit superior strength and sometimes ductility; however, the vast majority of results have been obtained in compression. Here, we examine the tensile as well as compressive properties, including fracture toughness, of Ti20Zr20Nb25Ta25Al10 RHEA at ambient to 1200 ℃. Two microstructures, comprising ordered B2 (brittle) and disordered A2 (ductile) phases, are compared after aging at 600°C and 800°C to change the fraction of these phases. In compression, both microstructures display considerable ductility exceeding 30% at elevated temperatures and 5%-15% at room temperature. However, under tensile loading, the mechanical properties are poor, with ductilities in the range of 0.1%-0.2% and fracture toughness values not exceeding 5 MPa.m^0.5, with brittle intergranular fracture most prevalent. We conclude that it is essential to evaluate refractory HEAs in tension as compression properties are likely to give an inadequate impression of the structural utility of the material.