Goel Lokesh, Mir Anamul H, Naveen Kumar N, Satyam Parlapalli V, Hinks Jonathan A, Donelly Stephen E, Tewari Raghvendra
Department of Engineering Sciences, Homi Bhabha National Institute, Anushakti Nagar, Trombay, Mumbai, Maharashtra 400094, India.
Materials Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai, Maharashtra 400085, India.
Microscopy (Oxf). 2021 Oct 5;70(5):461-468. doi: 10.1093/jmicro/dfab017.
The stability of β-precipitates in the Zr-1Nb alloy has been studied under Ne ion irradiation of energy 250 keV by insitu transmission electron microscope as a function of irradiation dose. The irradiation was carried out up to ∼136 dpa at 573 K. Microstructural investigations have shown that up to ∼38 dpa, precipitates showed an increase in size, and for irradiation doses >38 dpa, the size of the precipitates was noticed to reduce. Post-irradiation energy-dispersive spectrometry of the specimens revealed the Nb concentration throughout the matrix to be ∼0.8-1.5%. Three-dimensional atom probe tomography was also carried out for irradiated specimens to look for the presence of any nanoclusters. However, Nb clustering was not observed in the specimens. It is proposed that the dissolution of the precipitates may be facilitated by an increase in the solubility limit of Nb in Zr caused by irradiation. The solubility limit may increase by the introduction of defects generated by irradiation and by the destabilization of the β-phase. This may result in back-diffusion of Nb atoms to the matrix by radiation-enhanced diffusion to lower the strain produced by the defects, resulting in the dissolution of the precipitates.
通过原位透射电子显微镜研究了Zr-1Nb合金中β析出相在250 keV能量的Ne离子辐照下的稳定性与辐照剂量的关系。辐照在573 K下进行，直至约136 dpa。微观结构研究表明，在约38 dpa之前，析出相尺寸增大，而对于辐照剂量>38 dpa，析出相尺寸减小。对试样进行辐照后能量色散谱分析，结果显示整个基体中的Nb浓度约为0.8-1.5%。还对辐照后的试样进行了三维原子探针断层扫描，以寻找是否存在任何纳米团簇。然而，在试样中未观察到Nb团簇。据推测，辐照导致Zr中Nb的溶解度极限增加，可能促进了析出相的溶解。辐照产生的缺陷以及β相的失稳可能会使溶解度极限增加。这可能导致Nb原子通过辐射增强扩散向基体反向扩散，以降低由缺陷产生的应变，从而导致析出相溶解。
