B、Ti、Nb含量对激光熔覆FeCoCrNiAl高熵合金涂层组织与性能的影响

发布时间：2018-03-24 18:13

本文选题：高熵合金　切入点：FeCoCrNiAl涂层　出处：《沈阳工业大学》2017年硕士论文

【摘要】：高熵合金是近年来才被提出的一种新的合金设计理念。它的原理是在合金系统当中加入5种或者5种以上的合金元素,通过将每种合金元素含量控制在5%至35%之间,实现提高合金系统熵值的目的。高熵合金以其优异的力学性能在涂层制备方面具有广阔的应用空间。但是高熵合金体系过于庞大、涉及面广、发现时间短,因此涂层制备工艺以及元素含量对于其合金系统作用机理及实验数据尚不完善,急需进一步的研究。基于此本文利用扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)、维氏硬度计、多功能试验机等多种手段研究了B、Ti、Nb含量对于Fe CoCrNiAl高熵合金涂层组织结构的影响,并对比了直接激光熔覆与等离子喷涂预制后激光重熔两种工艺对涂层的影响结果,系统的研究了高熵合金组织的形成机理及相演变过程,测试了涂层力学性能并分析了影响因素。研究结果表明:直接进行激光熔覆与先使用等离子喷涂预制涂层之后激光重熔后涂层相比,激光重熔对于基体热输入较低,熔池较浅,但两种涂层的相组成与力学性能相差并不大。B、Ti、Nb元素都对Fe CoCrNiAl高熵合金涂层组织结构起到明显的晶粒细化作用。B含量升高的过程中,FCC相减少而BCC相增多;Ti加入后FCC相消失,产生BCC2相;而加入Nb后产生FCC2相。经过维氏硬度检测,FeCo Cr NiAlB0.75、Fe Co Cr NiAlTi、FeCo CrNiAlNb0.5涂层硬度为各合金系最大,分别为726Hv、966Hv、773Hv。各涂层在硬度达到最大的同时,耐磨性能也随之达到最大。经研究发现,B与Ti都为BCC相形成元素,而Nb为FCC相形成元素。B与Ti对于Fe CoCrNiAl系高熵合金涂层组织及性能的作用机理相类似,力学性能随元素含量增大而提高。而Nb元素添加后在合金组成为Fe Co CrNiAlNb0.5时达到硬度最大值,随Nb含量继续添加出现下降趋势。
[Abstract]:High entropy alloy is a new concept of alloy design that was developed recently. Its principle is to add 5 or more than 5 kinds of alloy elements in the alloy system, through each kind of alloy element content is controlled in the range of 5% to 35%, improve the alloy system entropy has a broad application space. High entropy alloy with excellent mechanical properties in coating preparation. But high entropy alloy system is too large, involving a wide range, that time is short, so the coating preparation process and content for the alloy system mechanism and the experimental data is not perfect, the urgent need for more research. This paper based on SEM (SEM), energy dispersive spectroscopy (EDS), X ray diffraction (XRD), Vivtorinox hardness, multi-function testing machine and other means of B, Ti, Nb content on coating microstructure of Fe high entropy alloy CoCrNiAl influence, and compared directly The effect of laser cladding and prefabricated after plasma spraying laser remelting process of two kinds of coatings, systematic study on the formation mechanism of microstructure of high entropy alloy and phase transformation process, testing the mechanical properties of the coating are analyzed. The results show that: directly after laser cladding and plasma spraying coating using prefabricated laser after laser remelting remelting coatings compared to the substrate heat input is low, the molten pool is shallow, but the two kinds of coating phase composition and mechanical properties of a little.B, Ti, Nb elements on coating microstructure of Fe high entropy alloy CoCrNiAl to grain refinement effect of.B was significantly increased in FCC phase decreased and BCC phase increased; the addition of Ti FCC phase BCC2 phase; disappeared, and after joining the Nb FCC2 phase. After Vivtorinox FeCo Cr hardness testing, NiAlB0.75, Fe Co Cr NiAlTi FeCo CrNiAlNb0.5, the hardness of coating Gold is the largest, respectively 726Hv, 966Hv, 773Hv. coating reached the maximum while the hardness, wear resistance also will reach the maximum. The study found that B and Ti are BCC phase forming elements, and Nb is the FCC phase formation mechanism of elements.B and Ti on the microstructure and properties of high entropy alloy coating Fe CoCrNiAl similar mechanical properties with element content increased. While the Nb element was added in the alloy composition of Fe Co CrNiAlNb0.5 reached the maximum hardness, with Nb content to add a declining trend.

【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG174.4

【参考文献】