摘要
The effects of nanostructuring on the mechanical and dry-sliding wear behaviors of a FeCoNi medium-entropy alloy(MEA)were systematically investigated through nano-indentation and ball-on-disc wear tests.The results show that reducing the grain size down into the nano-meter regime,on the one hand,significantly elevates the hardness of the FeCoNi alloy,and on the other hand,facilitates the formation of a surface oxide layer.As a result,the wear rate of the nanocrystalline(NC)FeCoNi alloy is one order of magnitude lower than its coarse-grained counterpart.The NC FeCoNi alloy also exhibits obviously enhanced wear resistance compared with conventional NC Ni and Ni-based alloys in terms of both lower wear rate and friction coefficient.Such enhancement in tribological properties mainly stems from the improved strain hardening ability,owing to the inevitable concentration heterogeneity in MEA that imposes extra resistance to dislocation motion.
通过纳米压痕测试和球盘摩擦实验,系统研究结构纳米化对FeCoNi中熵合金力学行为及干滑动摩擦磨损性能的影响。结果表明,将晶粒尺寸减小至纳米尺度,一方面显著提高了合金的硬度,另一方面促进了表面氧化层的形成。二者的共同作用使纳米晶FeCoNi合金的磨损率比粗晶合金低了一个数量级。与传统的纳米晶Ni及Ni基合金相比,纳米晶FeCoNi合金具有显著降低的磨损率和摩擦系数,表现出优异的耐磨性。这主要是由于纳米晶FeCoNi合金中本征的微尺度成分起伏能够有效阻碍位错滑移,使合金的应变硬化能力显著提高所致。
基金
supported by the Science and Technology Development Program of Jilin Province,China(No.20160520007JH)
the Major Science and Technology Special Project in Jilin Province,China(No.20210301024GX)
the National Natural Science Foundation of China(Nos.51601067,51775266,52301169).
