Si对AlCoCrFeNi高熵合金热腐蚀行为的影响  

Effect of Si Addition on Hot Corrosion Behavior of AlCoCrFeNi High Entropy Alloys

作　　者：张平[1] 李远田 张金勇 陈正[1] 樊宇[1] 沈宝龙[1] Zhang Ping;Li Yuantian;Zhang Jinyong;Chen Zheng;Fan Yu;Shen Baolong(School of Materials Science and Physics,China University of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]中国矿业大学材料与物理学院,江苏徐州221116

出　　处：《稀有金属材料与工程》2021年第10期3640-3647,共8页Rare Metal Materials and Engineering

基　　金：国家重点研发计划(2018YFB2001204);中央高校基本科研业务费(2019XKQYMS10)。

摘　　要：采用真空电弧熔炼法制备了AlCoCrFeNiSi_(x)(x=0,0.2,0.5,0.8,1.0)高熵合金,利用75%Na_(2)SO_(4)+25%NaCl(质量分数,下同)热盐涂覆的方法,对比研究了Si的添加及其含量对等摩尔比AlCoCrFeNi高熵合金在950℃下热腐蚀行为的影响。结果表明:经100 h热腐蚀后,由于发生Al的选择性氧化,合金表层相组成由bcc转变为fcc。适量Si的添加,会促使合金表面快速生成单一Al_(2)O_(3)膜,提高合金的热腐蚀抗力。但随着Si含量的增加,合金表面生成了由Al_(2)O_(3)和富Cr-Fe-Co-Si的尖晶石氧化物组成的混合氧化产物,且在氧化膜内应力和腐蚀性介质(氧化-硫化-氯化)的协同作用下,组织疏松易脱落,合金发生严重的内氧化和内硫化。AlCoCrFeNiSi_(x)(x=0,0.2,0.5,0.8,1.0)high entropy alloys were prepared by vacuum are melting.The effects of Si addition and its content on the hot corrosion behavior of AlCoCrFeNi alloys at 950℃ in mixed salt of 75%Na_(2)SO_(4)+25%NaCl(mass fraction)were investigated.The results show that the surface phase composition of the alloys changes from bee to fee due to selective oxidation of Al after 100 h hot corrosion.A single Al_(2)O_(3) scale forms preferentially on the surface of the alloy by adding proper amount of Si,and the hot corrosion resistance of the alloy improves significantly.However,the mixed oxides scales mainly compose of Al_(2)O_(3) and Cr-Fe-Co-Si enriched spinel oxides formed on the surfaces of the alloys with the increase of Si content.Under the synergistic action of the growth stress of mixed oxides scale and the multi-element corrosion medium(oxidization-vulcanization-chlorination),the oxide scales are loose and easy to fall off,and serious internal oxidation and vulcanization are observed in the alloys.

关 键 词：高熵合金 AlCoCrFeNi Si合金化 热腐蚀 

分 类 号：TG178[金属学及工艺—金属表面处理]