“Self-sharpening” tungsten high-entropy alloy

• Published in: Acta materialia Vol. 186; pp. 257 - 266
• Main Authors: Liu, Xing-Fa, Tian, Zhi-Li, Zhang, Xian-Feng, Chen, Hai-Hua, Liu, Tian-Wei, Chen, Yan, Wang, Yun-Jiang, Dai, Lan-Hong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-03-2020
• Subjects: Dynamic recrystallization; High-entropy alloy; Self-sharpening; Shear band; Tungsten alloy; Self-sharpening; Dynamic recrystallization; Tungsten alloy; Shear band; High-entropy alloy
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2020.01.005

“Self-sharpening”, a material maintaining its acute head shape during penetration, is highly desirable in a wide range of engineering applications. However, it remains a great challenge to make it occur in conventional single-principal-element alloys. Here, we develop a new chemical-disordered multi-phase tungsten high-entropy alloy that exhibits outstanding self-sharpening capability, in sharp contrast to conventional tungsten alloys only showing mushrooming. This alloy consists of a BCC dendrite phase and a rhombohedral μ phase embedded in the continuous FCC matrix, and such a unique microstructure leads to a 10–20% better penetration performance than conventional tungsten heavy alloys. We show that emergence of the self-sharpening is triggered by the ultrastrong μ phase stimulated dynamic recrystallization softening mediated shear banding. This study sheds light on the origin of self-sharpening and might open new opportunities for developing high-performance penetrator materials.
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