摘要
采用电沉积法制备出等原子比的纳米晶FeCoNi中熵合金和纳米晶纯Ni,并基于纳米压痕对两种材料的力学性能和蠕变行为进行了研究。微观结构表征发现,纳米晶FeCoNi中熵合金和纳米晶纯Ni均为单相面心立方结构,且晶粒尺寸接近。通过纳米压痕测试发现,相比较于纳米晶纯Ni,纳米晶FeCoNi中熵合金的硬度提升了1 GPa,并且抗蠕变性能显著增强。对强化机制和蠕变机制的分析发现,由于FeCoNi合金的层错能显著降低,导致纳米晶FeCoNi中熵合金的晶粒内部具有较多的纳米孪晶。中熵合金本征的短程有序结构会导致晶格畸变增大。在更多的纳米孪晶和更大的晶格畸变作用下,纳米晶FeCoNi合金的硬度提高;纳米晶FeCoNi合金中原子分布着复杂的晶界以及较低的层错能,使位错更容易在晶界处发射,结合层错/形变孪晶/短程有序结构对位错运动的阻碍作用,进而提升了纳米晶FeCoNi中熵合金的抗蠕变能力。
Equal-atomic ratio nanocrystalline(NC)FeCoNi medium-entropy alloy(MEA)and NC pure Ni were prepared by electrodeposition method.Based on nano-indentation,the mechanical properties and creep behavior of the two materials were investigated.The microstructure characterization reveals that both the NC FeCoNi MEA and NC pure Ni show single face-centered cubic(FCC)structures and the grain sizes are similar.By nano-indentation tests,compared with NC pure Ni,the hardness of NC FeCoNi MEA increases by 1 GPa,and its creep resistance is significantly enhanced.The analysis of strengthening mechanism and creep mechanism reveals that due to the significant reduction in the stacking fault energy of the NC FeCoNi MEA,there are nano-twins in the grain interiors of the NC FeCoNi MEA.The inherent short-range ordered structure of the medium-entropy alloy leads to an increase in lattice distortion.More naono-twins and higher lattice distortion enhance the hardness of the NC FeCoNi alloy.The distribution of complex grain boundaries and the low stacking fault energy in the atomis of NC FeCoNi MEA facilitate the easier emission of dislocations at the grain boundaries,while have the inhibitory effect on the movement of dislocations by the layer dislocation/dislocation twin/short-range ordered structures,thereby improving the creep resistance of the NC FeCoNi MEA.
作者
陈岩
李斯恩
韩双
CHEN Yan;LI Si-en;HAN Shuang(China Nonferrous Metals Innovation Institute(Tianjin)Co.,Ltd.,Tianjin 300393,China;BYD Automobile Co.,Ltd.,Xi′an 710119,China;College of Materials Science and Engineering,Jilin University,Changchun 130025,China)
出处
《塑性工程学报》
北大核心
2025年第7期165-174,共10页
Journal of Plasticity Engineering
基金
国家自然科学基金资助项目(51601067)。
关键词
纳米压痕
纳米晶
中熵合金
蠕变行为
nano-indentation
nanocrystalline
medium-entropy alloys
creep behavior
