Enhancing plasticity of ‘self-sharpening’ tungsten high-entropy alloy via tailoring μ-precipitation

Abstract

In our recently published work (Acta Materialia 186 (2020) 257–266), we have designed a new equimolar tungsten high-entropy alloy with excellent penetration ability to satisfy the highly desirable of ‘self-sharping’ in wide range of engineering application. This alloy has outstanding dynamic compressive properties and superior penetration performance than that of 93 W alloys. In this work, the tension properties of the tungsten high-entropy alloy were significantly improved by μ phase precipitation design strategy to tailor the morphology and distribution of μ phase. Through controlling the phase transformation process, the μ phase changes from liquid-solid phase transformation to solid-solid precipitation phase transformation. This can effectively impede the brittleness caused by the μ phase segregation at the grain boundary and phase boundary. Moreover, the Orowan effect caused by nano-sized μ -phase particles improves the tensile strength effectively (enhancing ∼150%) and ensure the ductility. This material design strategy significantly improves the tension ductility of the alloy and provides a new paradigm to solve the similar problem of material brittleness.

Keywords

• high-entropy alloys
• precipitation
• phase transformation
• plasticity