Temperature Dependence of Fracture Behavior and Mechanical Properties of AISI 316 Austenitic Stainless Steel
Temperature Dependence of Fracture Behavior and Mechanical Properties of AISI 316 Austenitic Stainless Steel
复制标题
AISI 316 奥氏体不锈钢断裂行为和机械性能的温度依赖性
DOI：
10.3390/met12091421
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发表时间：
2022-09-01
期刊：
影响因子：
2.9
通讯作者：
Rong, Lijian
中科院分区：
文献类型：
--
作者：
Lv, Xinliang;Chen, Shenghu;Rong, Lijian
通过对AISI 316奥氏体不锈钢在20 ℃ ~ 750 ℃温度范围内拉伸试验过程中的断口和金相分析，研究了AISI 316奥氏体不锈钢的断裂行为和变形模式，阐明了力学性能的温度依赖性。由于相对低的SFE（堆垛层错能），在20 ℃下的拉伸试验期间观察到平面滑移变形模式。在350-550 ℃范围内观察到明显的平面滑移特征，由此产生的局部变形导致剪切带的形成。高于550 ℃时位错更容易交叉滑移，导致胞状/亚晶粒结构的形成。在350-550 ℃范围内，剪切带中的优先微孔萌生和随后的各向异性生长行为导致断裂表面上的大尺寸和浅的韧窝。然而，在高于550 ℃的局部颈缩区域中，微孔倾向于沿拉伸方向沿着伸长，导致小尺寸和深的凹坑。剪切局部化降低了均匀变形能力，加速了沿着剪切带的断裂过程，导致在350-550 ℃范围内的均匀伸长率和总伸长率的平台。通过持续颈缩耐受局部变形的更高能力导致高于550 ℃的总伸长率的显著增加。
A combination of fractographic and metallographic analysis during tensile tests over the temperature ranging from 20 degrees C to 750 degrees C were carried out to investigate the fracture behaviors and deformation modes so as to clarify the temperature dependence of mechanical properties of AISI 316 austenitic stainless steel. Planar slip mode of deformation was observed during tensile tests at 20 degrees C due to a relatively low SFE (stacking fault energies). Pronounced planar slip characteristics were observed in the range of 350-550 degrees C, and the resultant localized deformation led to the formation of shear bands. The dislocation cross-slip was much easier above 550 degrees C, leading to the formation of cell/subgrain structures. The preferential microvoid initiation and subsequent anisotropic growth behavior in the shear bands led to large-size and shallow dimples on the fracture surfaces in the range of 350-550 degrees C. However, the microvoid tended to elongate along the tensile direction in the localized necking region above 550 degrees C, resulting in small-size and deep dimples. The shear localization reduced the uniform deformation ability and accelerated the fracture process along shear bands, leading to a plateau in uniform elongation and total elongation in the range of 350-550 degrees C. The higher capability to tolerate the localized deformation through sustained necking resulted in a significant increase in the total elongation above 550 degrees C.