固溶元素对二元镍基合金的微结构及其抗辐照性能的影响

Effects of solid solution elements on microstructures and radiation resistance of binary nickel based alloys

采用2 MeV的Ne离子对Ni、Ni-Cr和Ni-Mo合金进行辐照,开展固溶元素对二元镍基合金辐照性能影响的研究。对辐照后样品进行掠入射X射线衍射(Grazing Incidence X-ray Diffraction,GIXRD)分析发现,Ni、Ni-Cr、Ni-Mo合金晶格均未发生明显的畸变,也没有明显的析出相形成。纳米压痕结果表明:离子辐照导致了Ni、Ni-Cr和Ni-Mo合金硬化,当辐照损伤达到0.5~3.0 dpa(displacement per atom)时,Ni-Cr与Ni-Mo合金出现了硬化饱和现象,而Ni的硬化并未饱和。根据Orowan模型,分析了合金辐照硬化的机理;利用Makin-Minter方程,发现Ni-Mo合金的抗辐照能力优于Ni-Cr合金,而低幂次方程显示Ni具备随辐照量增加继续硬化的趋势。

[Background]In recent years,nickel based alloys have been used as candidate structural materials for the advanced fission reactor.Radiation effects on nickel based alloys have been widely studied whilst little attention has been paid to the effects of solid solution elements on irradiation of nickel based alloys.[Purpose]This study aims to understand the effects of Mo and Cr on the radiation resistance of binary nickel-based alloys.[Methods]First of all,Ni,Ni-Cr and Ni-Mo alloy samples were irradiated by 2 MeV Ne ions at room temperature.The irradiation fluxes were set 1.6×10^15 ions·cm^?2,3.2×1015 ions·cm^?2 and 9.6×10^15 ions·cm^?2,respectively.Then the grazing incidence Xray diffraction(GIXRD)was employed to investigate the microstructure changes of the samples,and the nanoindentation technique was used to measure the hardness of irradiated samples.[Results]GIXRD results show that the crystal lattices of Ni,Ni-Cr and Ni-Mo alloys have no obvious distortion,and no precipitated phase is formed.Nano indentation results show that ion irradiation causes hardening of Ni,Ni-Cr and Ni-Mo alloys.When the irradiation damage reaches 0.5~3.0 dpa(displacement per atom),the hardening of Ni-Cr and Ni-Mo alloys approaches saturation while the hardening of Ni is unsaturated.Finally,the mechanism of irradiation hardening was analyzed by using Orowan model and Makin-Minter equation.[Conclusions]The radiation resistance of Ni-Mo alloy is better than that of Ni-Cr alloy.Ni has the tendency of continuous hardening with the increase of radiation.