Ti对ODS型FeCrAl合金表面氧化铝层中活性元素Y扩散的影响  

Effect of Ti on the Diffusion of Reactive Element Yttrium in Alumina Coatings on the Surface of ODS FeCrAl Alloy

作　　者：黄太红[1] 宋鹏[1] 易健宏[1] HUANG Tai-hong;SONG Peng;YI Jian-hong(Faculty of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China)

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093

出　　处：《材料保护》2020年第4期1-8,34,共9页Materials Protection

摘　　要：利用机械合金化制备的氧化钇弥散强化(ODS)型FeCrAl合金广泛地应用于高温以及极端恶劣环境中。高温服役过程中FeCrAl合金表面形成致密且粘结性能好的氧化铝层是其抗高温、耐腐蚀的主要原因。同时,氧化铝层的综合性能特别是粘结性能极易受钇、铪、钛、硫等微量元素的影响。为此,结合表面形貌分析、断面形貌分析以及成分分析结果,主要研究了在高温环境中(1200℃)微量元素Ti对FeCrAl高温合金表面氧化铝层生长行为以及活性元素Y扩散的影响。结果表明:Ti的存在可以促进活性元素Y的向外扩散,在氧化铝层表面形成富含Y和Ti的氧化物。利用第一性原理计算,发现微量元素Ti在氧化铝层晶界上的扩散速率较快,同时微量元素Ti的添加改变了氧化铝层的热膨胀系数,提高了氧化铝层的粘结性能。Yttrium oxide dispersion strengthened FeCrAl alloy prepared by mechanical alloying are widely used in high temperature and extreme environments.The formation of dense and good adhesion alumina coatings on the surface of FeCrAl alloy is the main reason for its resistance to high temperature and corrosion during high-temperature service process.Meanwhile,the properties of the alumina coatings,especially the adherence,are seriously affected by trace elements such as yttrium,hafnium,titanium and sulfur.Therefore,the effects of trace element Ti on the diffusion of reactive element Y in the alumina coating on the surface of the FeCrAl alloy and the oxidation behavior during high temperature oxidation(1200℃)were studied by combing the results of surface morphology,cross section morphology and composition analysis.Results showed that the existence of Ti could promote the outside diffusion of active element Y,and therefore an oxide layer with Y and Ti formed on the alumina coating surface.By using the first principle calculation,it was found that the diffusion rate of element Ti on the grain boundary of the alumina coatings was faster,and the addition of trace element Ti changed the thermal expansion coefficient of alumina coatings,which improved the adhesion performance of the alumina coatings.

关 键 词：活性元素Y 氧化铝层 扩散 ODS型FeCrAl合金 FeCrAl高温合金 微量元素Ti 

分 类 号：TG174.4422[金属学及工艺—金属表面处理]