Multiplicity of dislocation pathways in a refractory multiprincipal element alloy

Area of Science:

• Materials Science
• Metallurgy
• Solid Mechanics

Background:

• Refractory multiprincipal element alloys (MPEAs) are critical for high-stress applications.
• Body-centered cubic (bcc) MPEAs require novel deformation mechanisms for enhanced performance.
• Understanding plastic deformation is key to unlocking MPEA potential.

Purpose of the Study:

• To investigate the deformation mechanisms in a body-centered cubic (bcc) refractory multiprincipal element alloy (MPEA).
• To correlate atomic structure with plastic deformability and strength in MoNbTi.
• To provide insights for designing high-performance MPEAs across a wide temperature range.

Main Methods:

• Experimental observation of dislocation motion.
• Atomistic calculations to simulate dislocation behavior.
• Mechanical testing to evaluate strength and deformability.

Main Results:

• The MoNbTi alloy demonstrates a balance of homogeneous plastic deformability and high strength.
• Dislocation motion is governed by a rugged atomic environment, favoring nonscrew dislocations.
• Multiple slip planes facilitate dislocation glide, contributing to the alloy's ductility.

Conclusions:

• The unique dislocation behavior in MoNbTi supports theories on high-temperature strength in similar alloys.
• A defect-aware approach to alloy design is crucial for materials operating across temperature extremes.
• This study advances strategies for developing advanced MPEAs for structural applications.