About this Abstract |
Meeting |
MS&T21: Materials Science & Technology
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Symposium
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High Entropy Materials: Concentrated Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond II
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Presentation Title |
Microstructure and Mechanical Properties of Hf-27Ta and Hf-21Ta-21X (X is Nb, Mo or W) Alloys |
Author(s) |
Oleg N. Senkov, Tinuade Daboiku, Todd Butler, Michael Titus, Noah Philips, Eric Payton |
On-Site Speaker (Planned) |
Oleg N. Senkov |
Abstract Scope |
The microstructure and mechanical properties of Hf-Ta-M alloys (M is Mo, Nb or W) are reported. The microstructure of Hf-27Ta consisted of coarse primary HCP particles and a monotectoidally transformed nano-lamella mixture of Ta-rich BCC and Hf-rich HCP phases. Hf-21Mo-21Ta consisted of a BCC matrix phase and HCP precipitates. Hf-21Nb-21Ta contained spherical nano-precipitates inside BCC matrix grains and two-phase BCC lamellar regions at grain boundaries. Hf-21Ta-21W had a Hf-rich HCP matrix, W-rich cubic Laves phase and monotectoidally transformed regions of Ta-rich BCC and Hf-rich HCP nano-lamellae. Hf-27Ta had yield stress of 1708 MPa at 25°C. Additions of Nb, Mo or W decreased the 25°C yield stress to 832 MPa, 1496 MPa or 1475 MPa, respectively. Hf-21Mo-21Ta was the strongest alloy at T ≥ 1000°C. Its yield stress at 1000°C, 1200°C and 1400°C was 943 MPa, 421 MPa and 146 MPa, respectively. Relationships between the microstructure and mechanical properties are discussed. |