The alloy system Al-Cr-Fe-Ni provides means for developing novel duplex materials composed of face-centered cubic (FCC) and body-centered cubic (BCC) phases with nearly equal volume fraction. We performed an alloy development study starting from the medium entropy alloy AlCrFe₂Ni₂ and adding small amounts of molybdenum in the following series (at.%): Al₁₇Cr₁₇Fe₃₃Ni₃₃, Al₁₇Cr₁₇Fe₃₃Ni₃₃Mo₁, Al₁₆Cr₁₆Fe₃₃Ni₃₃Mo₂, and Al₁₆Cr₁₆Fe₃₃Ni₃₃Mo₃. We focused the research on samples with an ultrafine vermicular duplex microstructure, a unique structure requiring sufficiently high cooling rates to suppress the conventional Widmanstätten colony formation. The samples were produced by arc melting in buttons of 300 g each. We characterized the microstructure of the samples using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and electron backscatter diffraction (EBSD). The EBSD data revealed significant strain in the FCC phase resulting from the BCC→FCC phase transformation. We investigated mechanical properties of the samples by micro-indentation and 3-point bending in a miniature testing device. The test specimens were in the as-cast condition, as well as in distinct annealed conditions. Annealing treatments were carried out at 950 and 1100°C under argon. The annealing lasted from 10 min to 6 h, followed by water quenching. Prolonged annealing at 950°C of Mo-containing samples resulted in the formation of sigma-phase. Annealing at 1100°C safely avoided sigma-phase formation, while leading to a good balance between the flexural strength and ductility of these samples. Mechanical testing also included the well-established superduplex steel 1.4517 (DIN EN 10283/ASTM A890) as reference material.

合金体系Al-Cr-Fe-Ni提供了开发新型双相材料的方法，该双相材料由面心立方（FCC）相和体心立方（BCC）相组成，其体积分数几乎相等。我们从中熵合金AlCrFe ₂ Ni ₂开始，并按以下系列（原子百分比）添加少量钼进行了合金开发研究：Al ₁₇ Cr ₁₇ Fe ₃₃ Ni ₃₃，Al ₁₇ Cr ₁₇ Fe ₃₃ Ni ₃₃ Mo ₁，Al ₁₆ Cr ₁₆ Fe ₃₃ Ni ₃₃ Mo ₂和Al₁₆ Cr ₁₆ Fe ₃₃ Ni ₃₃ Mo ₃。我们将研究重点放在具有超细蠕虫状双链体微观结构的样品上，该结构具有独特的结构，需要足够高的冷却速率以抑制传统的Widmanstätten菌落的形成。通过在每个300 g的纽扣中进行电弧熔化来生产样品。我们使用扫描电子显微镜（SEM），能量色散X射线光谱（EDS）和电子背散射衍射（EBSD）对样品的微观结构进行了表征。EBSD数据显示BCC→FCC相变导致FCC相出现明显应变。我们在微型测试设备中通过微压痕和三点弯曲研究了样品的机械性能。试样处于铸态状态，并且处于不同的退火状态。在氩气下于950和1100℃下进行退火处理。退火持续10分钟至6小时，然后水淬。含Mo的样品在950°C下长时间退火导致形成σ相。在1100°C进行退火可以安全地避免形成σ相，同时在这些样品的弯曲强度和延展性之间实现了良好的平衡。机械测试还包括公认的超双相钢1.4517（DIN EN 10283 / ASTM A890）。