Influence of Processing Route on the Fracture Resistance of Equal Channel Angular Pressing Deformed Iron
Influence of Processing Route on the Fracture Resistance of Equal Channel Angular Pressing Deformed Iron
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DOI：
10.1002/adem.202201011
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发表时间：
2022-09-15
影响因子：
3.6
通讯作者：
Pippan, Reinhard
中科院分区：
文献类型：
--
作者：
Hohenwarter, Anton;Pippan, Reinhard
研究了使用加工路线 B-C 通过等角通道压制在 200 摄氏度下变形的纯铁 (Armco-iron) 的机械行为，重点关注断裂性能。特别是，根据弹塑性断裂力学来评估相对于最后变形步骤的不同样本方向的断裂韧性。此外，将结果与路线 A 加工的材料进行了全面比较。介绍了两种变形路线的微观结构特征，并讨论了潜在的微观结构-性能关系。尽管微观结构特征不同，但两种变形途径（A 和 B-C）都具有相当的强度。路线 A 包含几乎平行于挤出方向的带状且排列良好的结构。对于路线 B-C，微观结构排列相对于预裂纹方向旋转，并且晶粒结构更加不均匀。对于这两种变形路径，裂纹平面方向在断裂特征中起着重要作用。沿挤出方向的断裂韧性，路线A的断裂韧性相当低，路线B-C的断裂韧性显着增强。因此，路线 B-C 提供了获得具有高损伤容限和相当低的各向异性程度的严重塑性变形 (SPD) 材料的途径。
The mechanical behavior of pure iron (Armco-iron) deformed at 200 degrees C by equal angular channel pressing using processing route B-C is investigated with a focus on the fracture properties. In particular, the fracture toughness in terms of elastic-plastic fracture mechanics is evaluated for different specimen orientations with respect to the last deformation step. In addition, the results are comprehensively compared with material processed by route A. The microstructural features of both deformation routes are presented and the underlying microstructure-property relationships are discussed. Both deformation routes (A and B-C) lead to a comparable strength even though the microstructural features differ. Route A contains a banded and well-aligned structure almost parallel to the extrusion direction. For route B-C, the microstructural alignment is rotated with respect to the pre-crack orientation and the grain structure is more heterogeneous. For both deformation routes, the crack plane orientation plays a significant role in the fracture characteristics. The fracture toughness along the extrusion direction, with substantially low fracture toughness for route A, is markedly enhanced for route B-C. Consequently, route B-C offers a pathway to obtaining severe plastic deformation (SPD) materials with high damage tolerance and a considerably lower extent of anisotropy.