Design of Strong-Yet-Plastic Distorted High Entropy Intermetallic Alloys with Superior High Temperature Performance

Description

Intermetallic alloys are renowned for their remarkable strength, exceptional creep resistance, superior corrosion resistance, and intriguing functional properties like shape memory effect and superconductivity. Among these alloys, B2 (or ordered BCC) intermetallics have found extensive applications in shape memory actuators and aerospace structures. However, they suffer from a trade-off between strength and plasticity due to various factors, such as limited slip systems, a low relative mobility between screw and edge dislocations, and a lack of effective hardening mechanisms. Despite significant efforts invested in this area, little progress has been made to overcome these challenges, and the fundamental problem of developing intermetallic alloys that are both strong and plastic remains unresolved. In this proposal, we aim to tackle this issue by embracing the concept of high entropy alloys (HEAs). Specifically, we will focus on developing a specific B2 intermetallic system with multiple principal elements, incorporating the principles of HEAs. Unlike conventional intermetallic alloys, our approach involves creating highly distorted lattices. Our preliminary results indicate that such alloys may promote the activation of multiple slip systems, mitigate discrepancies in the movement of dislocations, and even trigger local structural transitions during deformation, resulting in exceptional mechanical properties across a wide temperature range. The outcome of our research will not only shed light on the fundamental mechanisms underlying the synergy between plasticity and strength in B2 high entropy alloys but also pave the way for the development of strong-yet-plastic intermetallic alloys with broad engineering applications. By exploring this innovative approach, we anticipate significant advancements in the understanding and application of intermetallic alloys, opening new avenues for designing materials with superior mechanical properties.