Microstructure and nanoindentation of the CLAM steel with nanocrystalline grains under Xe irradiation
Microstructure and nanoindentation of the CLAM steel with nanocrystalline grains under Xe irradiation
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DOI：
10.1016/j.jnucmat.2014.09.008
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发表时间：
2014-12
影响因子：
3.1
通讯作者：
Yongqin Chang;Jing Zhang;Xiaoling Li;Q. Guo;F. Wan;Long Yi
中科院分区：
文献类型：
--
作者：
Yongqin Chang;Jing Zhang;Xiaoling Li;Q. Guo;F. Wan;Long Yi
本研究初步研究了室温下500 keV的氙离子轰击对中国低活化马氏体（CLAM）纳米晶钢（mc -CLAM钢）的辐照效应，辐照剂量高达每原子5.3位移（dpa）。钢的最上层组织由平均直径为13 nm的纳米晶粒组成。低剂量注入后，纳米晶晶粒呈马氏体板条结构，并在NC-CLAM钢中引入了许多位错和高密度气泡。当辐照剂量达到5.3 dpa时，板条区域存在缠结位错网络，气泡尺寸增大。x射线衍射结果表明，辐照后晶体质量下降，纳米晶体明显变粗。在辐照作用下，NC-CLAM钢的晶粒生长可归因于热峰对晶界的直接影响。在辐照样品中，由于晶粒生长和辐照引入的缺陷，在表层存在压应力，而辐照引入的晶粒尺寸粗化和从表面到基体的缺陷梯度导致辐照NC-CLAM钢中存在拉应力。采用纳米压痕法评价辐照过程中力学性能的变化，结果表明：随着辐照剂量的增加，NC-CLAM钢的硬度增加，这是由于晶界与辐照引入缺陷之间的竞争造成的。
This work presents an early look at irradiation effects on China low activation martensitic (CLAM) steel with nanocrystalline grains (NC-CLAM steels) under 500 keV Xe-ion bombardment at room temperature to doses up to 5.3 displacements per atom (dpa). The microstructure in the topmost region of the steel is composed of nanocrystalline grains with an average diameter of 13 nm. As the samples were implanted at low dose, the nanocrystalline grains had martensite lath structure, and many dislocations and high density bubbles were introduced into the NC-CLAM steels. As the irradiation dose up to 5.3 dpa, a tangled dislocation network exists in the lath region, and the size of the bubbles increases. X-ray diffraction results show that the crystal quality decreases after irradiation, although the nanocrystals obviously coarsen. Grain growth under irradiation may be ascribed to the direct impact of the thermal spike on grain boundaries in the NC-CLAM steels. In irradiated samples, a compressive stress exists in the surface layer because of grain growth and irradiation-introduced defects, while the irradiation introduced grain-size coarsening and defects gradients from the surface to matrix result in a tensile stress in the irradiated NC-CLAM steels. Nanoindentation was used to estimate changes in mechanical properties during irradiation, and the results show that the hardness of the NC-CLAM steels increases with increasing irradiation dose, which was ascribed to the competition between the grain boundaries and the irradiation-introduced defects.