Spherical nanoindentation of proton irradiated 304 stainless steel: A comparison of small scale mechanical test techniques for measuring irradiation hardening
Spherical nanoindentation of proton irradiated 304 stainless steel: A comparison of small scale mechanical test techniques for measuring irradiation hardening
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DOI：
10.1016/j.jnucmat.2017.06.031
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发表时间：
2017-09
影响因子：
3.1
通讯作者：
J. Weaver;Siddhartha Pathak;A. Reichardt;H. Vo;S. Maloy;P. Hosemann;N. Mara
中科院分区：
文献类型：
--
作者：
J. Weaver;Siddhartha Pathak;A. Reichardt;H. Vo;S. Maloy;P. Hosemann;N. Mara
实验量化反应堆材料中辐射损伤的机械效应对于开发和鉴定新材料以提高性能和安全性是必要的。这可以通过离子束辐照和小规模机械测试的组合以高通量方式实现，这与反应堆辐照样品的批量测试的高成本和费力性质相反。目前的工作重点是使用球形纳米压痕应力-应变曲线对未辐照和质子辐照（10 dpa，360 °C）的304不锈钢，以量化辐射损伤的机械效应。球形纳米压痕应力-应变测量表明，辐射诱导的压痕屈服强度从1.36 GPa增加到2.72 GPa和10 GPa-30 GPa的压痕加工硬化率的辐射诱导的增加。这些测量值进行了严格比较，对布氏纳米硬度，微柱压缩，和微张力测量相同的材料和类似的晶粒取向。当通过球形纳米压痕或布氏纳米硬度测试测量时，辐照屈服强度与未辐照屈服强度的比率增加2倍。球形压痕应力-应变曲线的单轴（微柱和微张力）的应力-应变曲线的比较，实现了使用一个简单的比例关系，显示出良好的协议为未照射的条件和协议较差的后屈服行为的照射条件。球形纳米压痕和单轴应力-应变曲线之间的不一致可能是由于在单轴测试期间发生的塑性不稳定性，但在球形纳米压痕测试期间不存在。
Experimentally quantifying the mechanical effects of radiation damage in reactor materials is necessary for the development and qualification of new materials for improved performance and safety. This can be achieved in a high-throughput fashion through a combination of ion beam irradiation and small scale mechanical testing in contrast to the high cost and laborious nature of bulk testing of reactor irradiated samples. The current work focuses on using spherical nanoindentation stress-strain curves on unirradiated and proton irradiated (10 dpa at 360 °C) 304 stainless steel to quantify the mechanical effects of radiation damage. Spherical nanoindentation stress-strain measurements show a radiation-induced increase in indentation yield strength from 1.36 GPa to 2.72 GPa and a radiation-induced increase in indentation work hardening rate of 10 GPa–30 GPa. These measurements are critically compared against Berkovich nanohardness, micropillar compression, and micro-tension measurements on the same material and similar grain orientations. The ratio of irradiated to unirradiated yield strength increases by a similar factor of 2 when measured via spherical nanoindentation or Berkovich nanohardness testing. A comparison of spherical indentation stress-strain curves to uniaxial (micropillar and micro-tension) stress-strain curves was achieved using a simple scaling relationship which shows good agreement for the unirradiated condition and poor agreement in post-yield behavior for the irradiated condition. The disagreement between spherical nanoindentation and uniaxial stress-strain curves is likely due to the plastic instability that occurs during uniaxial tests but is absent during spherical nanoindentation tests.