In Situ Micro-Pillar Compression to Examine Radiation-Induced Hardening Mechanisms of FeCrAl Alloys
In Situ Micro-Pillar Compression to Examine Radiation-Induced Hardening Mechanisms of FeCrAl Alloys
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DOI：
10.2139/ssrn.3604622
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发表时间：
2020-06
期刊：
影响因子：
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通讯作者：
Yuchi Cui;E. Aydogan;J. Gigax;S. Maloy;Yongqiang Wang;A. Misra
中科院分区：
文献类型：
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作者：
Yuchi Cui;E. Aydogan;J. Gigax;S. Maloy;Yongqiang Wang;A. Misra
摘要 介绍了 300°C 5 MeV Fe2+ 离子辐照对 FeCrAl C26M 合金显微组织演变和变形行为的影响。已经发现，位错环密度从 1 dpa 到 16 dpa 辐照增加了一个数量级，而位错环尺寸随着损伤的增加而饱和。直径为 600 nm、高度为 1.3 µm 的微柱被制造并压缩在分别具有 、 和 晶体取向的晶粒内。 {112}已被确定为未辐照和辐照合金中的主要滑移系。观察到辐照后屈服应力的增加，沿 和 与沿 的变化可测量。通过应用Orowan分散势垒模型，发现屈服应力的增加主要是由于辐射产生的缺陷环的滑移阻力所致。进行了详细的透射电子显微镜（TEM）研究，以量化伯格斯矢量和高应变下辐照诱导位错的分布。结果表明，局部剪切不稳定性是由 1/2 位错滑出测试柱的雪崩滑移事件引起的。同时，在滑移带附近形成大量固着/不动位错，导致高应变下的硬化。
Abstract The effects of 5 MeV Fe2+ ion irradiation at 300°C on the microstructure evolution and deformation behavior of a FeCrAl C26M alloy are presented. It has been found that dislocation loop density increases an order of magnitude from 1 dpa to 16 dpa irradiations, whereas, the dislocation loop size saturates with increasing damage. Micropillars, 600 nm in diameter and 1.3 µm in height, were fabricated and compressed inside grains with , and crystallographic orientations, respectively. {112} has been identified as the primary slip system in both unirradiated and irradiated alloys. The increase in yield stress after irradiation is observed with measurable variation along and vs. along . By applying the Orowan dispersed barrier model, the increase of yield stress is found mainly due to the slip resistance of radiation generated defect loops. Detailed transmission electron microscopy (TEM) studies were performed to quantify the Burgers vector and the distribution of irradiation induced dislocations at elevated strains. It is revealed that localized shear instability is caused by avalanche slip events of ½ dislocations gliding out of tested pillars. Simultaneously, a large number of sessile/immobile dislocations formed in the vicinity of slip band, leading to the hardening at elevated strains.