Nb-Ti含量对FeCoNiCrNb_(x)Ti_(y)高熵合金熔覆层韧脆转变与耐腐蚀性能影响研究  

Effect of Nb-Ti Content on Ductile-brittle Transition and Corrosion Resistance of FeCoNiCrNb_(x)Ti_(y) High Entropy Alloy Cladding Layer

作　　者：卜善飞 姜芙林 魏长生 张耀辉 杨发展[1,2,3] 梁鹏 BU Shanfei;JIANG Fulin;WEI Changsheng;ZHANG Yaohui;YANG Fazhan;LIANG Peng(School of Mechanical and Automotive Engineering,Ministry of Education,Qingdao University of Technology,Shandong Qingdao 266520,China;Key Laboratory of Industrial Fluid Energy Saving and Pollution Control,Ministry of Education,Qingdao University of Technology,Shandong Qingdao 266520,China;Collaborative Innovation Center for Mechanized Production Equipment of Major Crops in Shandong Province,Shandong Qingdao 266109,China)

机构地区：[1]青岛理工大学机械与汽车工程学院,山东青岛266520 [2]青岛理工大学工业流体节能与污染控制教育部重点实验室,山东青岛266520 [3]山东省主要农作物机械化生产装备协同创新中心,山东青岛266109

出　　处：《表面技术》2024年第20期118-133,共16页Surface Technology

基　　金：山东省自然科学基金(ZR2022MEE081,ZR2021ME198);山东省主要农作物机械化生产装备协同创新中心开放课题项目(SDXTZX-21);高等学校学科创新引智计划(D21017)。

摘　　要：目的针对海工装备承载件工作时因耐腐性及强韧性不足而发生失效的问题,研究了元素含量对高熵合金熔覆层塑脆性转变与耐腐蚀性能的影响规律和作用机理。方法首先,在确定FeCoNiCrNbTi高熵合金体系的前提下,利用第一性原理计算方法对元素配比进行筛选,其次采用激光熔覆技术在典型海工装备材料42CrMo钢表面制备FeCoNiCrNb_(x)Ti_(y)高熵合金熔覆层,以探究Nb、Ti元素含量对高熵合金熔覆层韧脆转变与耐腐蚀性能的影响规律与机理。结果通过第一性原理计算得出FeCoNiCrNbTi高熵合金FCC相和BCC相的晶格常数均随着Ti含量的上升而下降,且这种下降趋势逐渐减缓;在涂层的物相中熔覆层主要由FCC相、BCC相以及Laves相组成,随着Nb含量的增加,Laves相衍射峰增强,而随着Ti含量的增加,BCC相衍射峰增强,Laves相中出现含Ti的化合物,并且组织中出现富Ti区;随着Nb与Ti含量的增加,熔覆层硬度均呈现上升趋势,但其抗拉强度及延伸率均呈下降趋势,并且当Nb元素含量与Ti元素的原子比分别增加至0.3和0.5时,其断裂方式实现由韧性断裂到脆性断裂的转变;随着Nb与Ti含量的增加,其耐腐蚀性因组织结构分布不均以及缺陷的产生而逐渐变差。结论物相占比以及组织结构的分布是影响高熵合金熔覆层力学性能、断裂方式和耐腐蚀性的主要因素。在FeCoNiCrNbTi高熵合金中,BCC相及Laves相的增加均有利于显微硬度的提升,但会导致抗拉强度和延伸率变差,甚至发生韧脆转变;而且多种物相的生成破坏了组织成分的均匀性,甚至产生裂纹等缺陷,成为耐腐蚀性变差的主导因素。The work aims to study effect of element content on the plastic-brittle transition and corrosion resistance of high-entropy alloy cladding layers,so as to solve the failure of marine equipment bearing parts due to insufficient corrosion resistance and strength and toughness during operation.Firstly,on the premise of using FeCoNiCrNbTi high-entropy alloy system to modify the surface of marine equipment such as ship stern shaft,the element ratio of the high-entropy alloy system was further screened and evaluated according to the first-principles calculation method.The element ratio range of FeCoNiCrNbTi high-entropy alloy was determined.Then,FeCoNiCrNbTi high-entropy alloy was cladded on the surface of typical marine equipment material 42CrMo steel by laser cladding technology to form an FeCoNiCrNb_(x)Ti_(y) high-entropy alloy cladding layer to explore the influence law and mechanism of Nb and Ti content on the ductile-brittle transition and corrosion resistance of the FeCoNiCrNbTi high-entropy alloy cladding layer.The results showed that the lattice constants of FCC phase and BCC phase of FeCoNiCrNbTi high entropy alloy decreased with the increase of Ti content,and the decreasing trend gradually slowed down with the increase of Ti content.Through XRD test,it was found that the cladding layer in the phase of the coating was mainly composed of FCC phase,BCC phase and Laves phase.In the cladding layer of the high entropy alloy,with the increase of Nb content,the Laves phase diffraction peak in the cladding layer showed an increasing trend.With the increase of Ti,the BCC phase diffraction peak in the cladding layer showed an increasing trend.It was worth noting that Ti-containing compounds also appeared in the Laves phase.Combined with the scanning electron microscope,it was found that Ti-rich regions also appeared in the FeCoNiCrNbTi high-entropy alloy cladding layer;In the hardness test of FeCoNiCrNbTi high entropy alloy cladding layer,it was found that with the increase of Nb and Ti content,the hardness of FeCoNiCr

关 键 词：高熵合金 激光熔覆 第一性原理计算 拉伸性能 耐腐蚀性 

分 类 号：TG133[一般工业技术—材料科学与工程]