Materials Science and Engineering, Ohio State University, 2041 College Rd, Columbus, OH, 43210, USA.
Nat Commun. 2018 Apr 10;9(1):1363. doi: 10.1038/s41467-018-03846-0.
CrCoNi alloy exhibits a remarkable combination of strength and plastic deformation, even superior to the CrMnFeCoNi high-entropy alloy. We connect the magnetic and mechanical properties of CrCoNi, via a magnetically tunable phase transformation. While both alloys crystallize as single-phase face-centered-cubic (fcc) solid solutions, we find a distinctly lower-energy phase in CrCoNi alloy with a hexagonal close-packed (hcp) structure. Comparing the magnetic configurations of CrCoNi with those of other equiatomic ternary derivatives of CrMnFeCoNi confirms that magnetically frustrated Mn eliminates the fcc-hcp energy difference. This highlights the unique combination of chemistry and magnetic properties in CrCoNi, leading to a fcc-hcp phase transformation that occurs only in this alloy, and is triggered by dislocation slip and interaction with internal boundaries. This phase transformation sets CrCoNi apart from the parent quinary, and its other equiatomic ternary derivatives, and provides a new way for increasing strength without compromising plastic deformation.
CrCoNi 合金表现出出色的强度和塑性变形的组合，甚至优于 CrMnFeCoNi 高熵合金。我们通过磁可调相变将 CrCoNi 的磁和机械性能联系起来。虽然两种合金都结晶为单相面心立方（fcc）固溶体，但我们发现 CrCoNi 合金中存在一种明显能量更低的六方密排（hcp）结构相。通过比较 CrCoNi 与 CrMnFeCoNi 的其他等原子三元衍生物的磁性构型，证实磁性受阻的 Mn 消除了 fcc-hcp 能量差。这突出了 CrCoNi 独特的化学和磁性组合，导致仅在该合金中发生 fcc-hcp 相变，并且由位错滑移和与内部边界相互作用触发。这种相变使 CrCoNi 与母体五元体及其它等原子三元衍生物区别开来，并为在不牺牲塑性变形的情况下提高强度提供了一种新方法。
