Cunningham W Streit, Gentile Jonathan M, El-Atwani Osman, Taylor Chase N, Efe Mert, Maloy Stuart A, Trelewicz Jason R
Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY, USA.
Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
Sci Rep. 2018 Feb 13;8(1):2897. doi: 10.1038/s41598-018-20990-1.
The unique ability of grain boundaries to act as effective sinks for radiation damage plays a significant role in nanocrystalline materials due to their large interfacial area per unit volume. Leveraging this mechanism in the design of tungsten as a plasma-facing material provides a potential pathway for enhancing its radiation tolerance under fusion-relevant conditions. In this study, we explore the impact of defect microstructures on the mechanical behavior of helium ion implanted nanocrystalline tungsten through nanoindentation. Softening was apparent across all implantation temperatures and attributed to bubble/cavity loaded grain boundaries suppressing the activation barrier for the onset of plasticity via grain boundary mediated dislocation nucleation. An increase in fluence placed cavity induced grain boundary softening in competition with hardening from intragranular defect loop damage, thus signaling a new transition in the mechanical behavior of helium implanted nanocrystalline tungsten.
由于晶界具有较大的单位体积界面面积，其作为辐射损伤有效汇的独特能力在纳米晶材料中起着重要作用。在作为面向等离子体材料的钨的设计中利用这一机制，为提高其在聚变相关条件下的抗辐射能力提供了一条潜在途径。在本研究中，我们通过纳米压痕探索了缺陷微观结构对氦离子注入纳米晶钨力学行为的影响。在所有注入温度下都明显出现了软化现象，这归因于气泡/空洞加载的晶界通过晶界介导的位错形核抑制了塑性起始的激活势垒。通量增加使空洞诱导的晶界软化与晶内缺陷环损伤导致的硬化相互竞争，从而表明氦注入纳米晶钨的力学行为出现了新的转变。
