激光熔覆含硼BCC结构高熵合金涂层强韧化机理研究

项目名称： 激光熔覆含硼BCC结构高熵合金涂层强韧化机理研究

项目编号： No.51271001

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 何宜柱

作者单位： 安徽工业大学

项目金额： 80万元

中文摘要： 激光熔覆含硼bcc结构FeCoNiCrAlCuBx(Y)高强度高熵合金涂层。针对高熵合金现有通过增加合金元素中大原子含量提高固溶体晶格畸变，但致晶格脆性迅速升高的主要强化方法。基于激光快速凝固动力学条件，避免最大限度提高涂层中超饱和间隙原子硼的含量和间隙固溶强化效果。依据高熵合金涂层特有的退火组织细化现象，结合晶体生长取向电子背散射衍射观察（EBSD），通过热处理工艺调控细晶强化和晶界强化等手段提高涂层强韧性水平。利用微/纳米压痕技术及其弹性模量、残余变形等测试结果研究涂层中超饱和固溶体的强韧化机制和变形机理；结合第一原理计算和组织、结构微观分析，研究组成元素之间混合焓、熔体黏度、电子结构、原子半径差异和原子占位对涂层相选择、相转化、组织和强韧性之间的关联机制；探讨多元复杂合金激光亚稳态凝固过程中的熔体结构和分凝行为，以及元素扩散在涂层中晶体形核和生长过程中的作用。

中文关键词： 含硼高熵合金；激光熔覆；硬度；断裂韧性；间隙固溶强化

英文摘要： High strength and high-entropy FeCoNiCrAlCuBx(Y) alloy coatings with bcc structure and boron addition will be prepared by laser cladding. For the reported strategy to strengthen the high-entropy alloy (HEA) by increasing large atom contents in the HEA composition invariably suffers from the rapidly increased brittleness because of the increased lattice distortion. This project aims at improving the coating strength and toughness by increasing the content of interstitial boron atom to enhance supersaturated solid solution strengthening effect and by controling the grain refinement and boundary strengthening during annealing treatment. The crystal growth orientation will be observed by electron backscatter diffraction (EBSD) technique. The strength, toughness and deformation mechanisms of the bcc supersaturated solid solution structure will be studied by nano-indentation and its elastic modulus, residual deformation test results. The relations of phase selection, microstructure, strength and toughness properties in the coating with the elements atomic radii, electronic constructions and atomic occupations in the crystal will be studied by the first principal calculation, microsturcture and phase analysis. The melt structure, segregation and the effects of component diffusion on the nucleation and growth of the cry

英文关键词： boron-containing high entropy alloy；laser cladding；hardness；fracture toughness；strengthening by interstitial solid solution