定向凝固Fe-18%Cr-3%B-Si合金组织及高温抗氧化性能  

Microstructure and High Temperature Oxidation Resistance of Directionally Solidified Fe-18wt.%Cr-3wt.%B-Si Alloy

作　　者：王天元 马胜超 程霜 陈翰韬 吕萍 王嘉琪 邢建东[1] 马胜强[1] WANG Tian-yuan;MA Sheng-chao;CHENG Shuang;CHEN Han-tao;LYU Ping;WANG Jia-qi;XING Jian-dong;MA Sheng-qiang(State Key Laboratory for Mechanical Behaviour of Materials,School of Materials Science and Engineering,Xi’an Jiaotong University,Xi’an 710049,China;Avic Shaanxi Aero Electric Co.,Ltd.,Xingping 713165,China)

机构地区：[1]西安交通大学材料科学与工程学院金属材料强度国家重点实验室,西安710049 [2]中航工业陕西航空电气有限责任公司,陕西兴平713165

出　　处：《表面技术》2021年第11期270-278,共9页Surface Technology

基　　金：国家自然科学基金(51771143,52071254);省级大学生创新创业项目资助(SJ202010698167)。

摘　　要：目的研究Si对Fe-18%Cr-3%B合金高温抗氧化性能的影响,并开发新型抗氧化轧辊材料。方法采用定向凝固技术制备出Si质量分数分别为0.0%、1.0%、2.0%、3.0%的Fe-Cr-B定向凝固合金,并用增重法表征合金的氧化动力学,通过SEM、XRD等手段分析定向合金氧化膜表面和截面形貌、结构和物相组成,并评价Si对定向合金抗氧化性能的作用。结果Si的加入明显细化了定向凝固Fe-Cr-B合金的组织,有利于合金中硬质相M_(2)B硼化物的定向生长。氧化结果表明,经800℃氧化100 h后,Si的加入可使合金氧化速率从0.05228 g/(m^(2)·h)降至0.00928 g/(m^(2)·h),抗氧化性能提升5倍以上。Si的加入使定向合金表面氧化膜变得光滑平整、致密连续且无开裂和剥落。表面膜结构分析表明,该定向合金氧化膜从合金基体到表面依次为Cr_(2)O_(3)、FeCr_(2)O_(4)、Fe_(3)O_(4)尖晶石和最外层的Fe_(2)O_(3)复合氧化物,而Si的加入促进了最内层SiO_(2)氧化膜的形成,该层呈连续曲折形态存在于定向合金与Cr_(2)O_(3)的界面。同时,定向合金中取向排列的M2B硬质相与内氧化层SiO_(2)呈现出“嵌入式”的嵌合界面,改变了界面结合形态和内界面结构,显著提高了复合氧化膜与定向合金界面的附着力。定向合金的氧化过程中,相对粗大的初生硼化物失效主要源于初生硼化物的剥落与氧内扩散诱致M2B开裂。结论Si显著提高定向Fe-Cr-B合金的抗氧化性,主要机制为Si促进内氧化层SiO_(2)的形成,并导致“互嵌入式”的SiO_(2)/M_(2)B双向嵌合界面结构的产生,这种氧化膜/合金界面“取向性互嵌型钉扎膜结构”可有效提高膜基界面附着力。The aims is to study the effect of Si on the high temperature oxidation resistance of Fe-18wt.%Cr-3wt.%B alloy and develop a new type oxidation-resistant roll material.Fe-Cr-B directional solidification alloys with Si content of 0.0wt.%,1.0wt.%,2.0wt.%,and 3.0wt.%were prepared by directional solidification technology and the oxidation kinetics of the alloys were characterized by the weight gain method.Analyze the surface and cross-sectional morphology,structure and phase composition of the oriented alloy oxide film by means of SEM,XRD and other means and evaluate the effect of Si on the oxidation resistance of the oriented alloy.The addition of Si significantly refines the structure of the directionally solidified Fe-Cr-B alloy,which is beneficial to the directional growth of the hard phase M2B boride in the alloy.The oxidation results show that the addition of Si can reduce the oxidation rate of the alloy from 0.05228 g/(m^(2)·h)to 0.00928 g/(m^(2)·h)after being oxidized at 800℃for 100 h,and the oxidation resistance is increased by more than 5 times.The addition of Si makes the surface oxide film of the oriented alloy smooth,compact and continuous without cracking and peeling.The analysis of the surface film structure shows that the oriented alloy oxide film is composed of Cr_(2)O_(3),FeCr_(2)O_(4),Fe_(3)O_(4) spinel and the outermost Fe_(2)O_(3) composite oxide from the alloy matrix to the surface.The addition of Si promotes the formation of the innermost SiO_(2) oxide film.The layer is in a continuous tortuous form at the interface between the oriented alloy and Cr_(2)O_(3).At the same time,the oriented M_(2)B hard phase and the internal oxide layer SiO_(2) in the oriented alloy present an“embedded”intercalation interface,which changes the interface bonding morphology and internal interface structure,and significantly improves the adhesion between the composite oxide film and the oriented alloy interface force.The failure of relatively coarse primary borides in the oxidation process of oriented alloys

关 键 词：FE-CR-B合金 定向凝固 界面形貌 钉扎结构 内氧化 硼化物 

分 类 号：TG132.3[一般工业技术—材料科学与工程]