CoCrFeMnNi高熵合金组织及电化学腐蚀性能研究

Microstructure and Electrochemical Corrosion Behavior of CoCrFeMnNi High Entropy Alloys

CoCrFeMnNi高熵合金因其优异的性能,是最先系统开发研究的高熵合金之一。本文以真空感应熔炼并冷轧处理的CoCrFeMnNi高熵合金为研究对象,借助X射线衍射仪、金相显微镜、维氏硬度计以及电化学腐蚀工作站等实验设备,研究了CoCrFeMnNi合金不同温度退火后显微组织及电化学腐蚀性能变化。CoCrFeMnNi高熵合金主要由面心立方的Fe-Ni相组成,在800℃左右退火热处理后产生了新相,但总体结构未发生明显的变化。对CoCrFeMnNi高熵合金进行退火热处理可以降低其硬化倾向,在大部分情况下可提升合金的耐腐蚀能力,但其趋势并非线性相关。退火温度为500℃、600℃、700℃时,合金硬度逐渐下降;而在800℃退火后,合金因发生固溶强化,硬度得以提高,随后在900℃退火后继续软化。此强化效果一定程度上提升了合金的耐腐蚀性,然而,500℃、600℃、700℃退火后,合金的耐腐蚀性能随退火温度升高而降低。

Due to its unique characteristics,CoCrFeMnNi high entropy alloy(HEA)is one of the first developed and studied HEAs.In this study,vacum induction melted and cold rolled CoCrFeMnNi high entropy alloy was selected as the research object.The microstructure variation and the corrosion properties after annealing at different temperatures were investigated in detail by means of X-ray diffraction,Vickers hardness tester,and electrochemical corrosion station.The CoCrFeMnNi high entropy alloy is mainly composed of face-centered cubic Fe-Ni phase.After annealing at about 800,a new phase is formed,but the structure does not change significantly.The annealing treatment of CoCrFeMnNi high entropy alloy can reduce the hardening tendency and improve the corrosion resistance of the alloy in most cases,but the trend is not linearly correlated.Compared with the three groups of experiments annealed at 500~700℃,the hardness of the alloy decreased gradually.However,after annealing at 800℃,the solid solution of the alloy is strengthened due to the microstructure change,and the hardness is increased,and then the alloy continues to soften after annealing at 900℃.This strengthening effect improves the corrosion resistance of the alloy to some extent.However,after annealing at 500~700℃,the corrosion resistance of the alloy decrease with the increase of annealing temperature.