Abstract Nanocrystalline Fe-based alloys have excellent soft magnetic properties, but their application is limited due to annealing induced embrittlement. In this work the embrittlement of flash annealed Fe85.2Si0.5B9.5P4Cu0.8 (at.%) ribbons was investigated using two-point bending and tensile tests as well as nanoindentation testing. In addition, fracture surfaces of notched tensile specimens were analyzed in dependence on annealing temperature and correlated to mechanical and structural transitions. The amorphous ribbons have been flash annealed for 10 s at temperatures between 330 °C and 540 °C under an applied tensile stress of 20 MPa. X-ray diffraction and atom probe tomography were used to analyze the phase formation, microstructure and elemental partitioning. The results of two-point bending tests show a sharp transition from ductile to brittle behavior at annealing temperatures between 330 °C and 350 °C. The stress intensity factor is decreasing from 70.4 MPa m to 3.2 MPa m . Thus, embrittlement takes place before the onset of crystallization at 400 °C. This embrittlement is related to a reduced shear band activity as a more localized shear activity during two-point bending. Nanoindentation results suggest a slight increase in the shear transformation zone volume, which could be related to a relaxation of free volume.

中文翻译：

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Fe 85.2 B 9.5 P 4 Cu 0.8 Si 0.5 金属玻璃带快速退火脆化研究

摘要 纳米晶铁基合金具有优异的软磁性能，但由于退火诱发脆化而限制了其应用。在这项工作中，使用两点弯曲和拉伸试验以及纳米压痕试验研究了快速退火 Fe85.2Si0.5B9.5P4Cu0.8 (at.%) 带的脆化。此外，根据退火温度并与机械和结构转变相关联，分析了缺口拉伸试样的断裂表面。非晶带已在 330°C 和 540°C 之间的温度下在 20 MPa 的拉伸应力下快速退火 10 秒。X射线衍射和原子探针断层扫描用于分析相形成、微观结构和元素分配。两点弯曲试验的结果表明，在 330 °C 和 350 °C 之间的退火温度下，从韧性行为到脆性行为的急剧转变。应力强度因子从 70.4 MPa m 下降到 3.2 MPa m 。因此，脆化发生在 400 °C 开始结晶之前。这种脆化与减少的剪切带活动有关，因为在两点弯曲期间更局部的剪切活动。纳米压痕结果表明剪切转变区体积略有增加，这可能与自由体积的松弛有关。这种脆化与减少的剪切带活动有关，因为在两点弯曲期间更局部的剪切活动。纳米压痕结果表明剪切转变区体积略有增加，这可能与自由体积的松弛有关。这种脆化与减少的剪切带活动有关，因为在两点弯曲期间更局部的剪切活动。纳米压痕结果表明剪切转变区体积略有增加，这可能与自由体积的松弛有关。