Microstructure and mechanical properties of refractory MoNbHfZrTi high-entropy alloy

• A new refractory MoNbHfZrTi high-entropy alloy with single BCC phase is prepared.
• The single disordered BCC phase has high structural stability.
• The compressive yield strength is 1719 MPa at room temperature.
• This alloy still has high compression yield strength at elevated temperatures.
• The dynamic recrystallization occurs during elevated-temperature compression.

The present paper reports the microstructure, phase stability and mechanical properties of a new refractory MoNbHfZrTi high-entropy alloy. MoNbHfZrTi alloy consists of a disordered body-centered cubic (BCC) solid solution phase in as-cast and homogenized states. Homogenization treatment and DSC analysis indicate that there is no any phase transition below 1743 K. At room temperature, the compressive yield strength for the alloy in as-cast and as-homogenized states reaches about 1719 MPa and 1575 MPa, respectively and the fracture mechanism is brittle quasi-cleavage fracture. At elevated temperatures, this alloy has compression yield strength of 825 MPa at 1073 K, 728 MPa at 1173 K, 635 MPa at 1273 K, 397 MPa at 1373 K and 187 MPa at 1473 K and some fine grains form at grain boundaries due to partial dynamic recrystallization.

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