含钨高熵合金组织和性能的研究

发布时间：2018-08-30 16:25

【摘要】：传统合金体系均以一种或者两种元素为主,合金的性质受制于主元素,且传统合金设计理念认为合金系统中主元数越多,则越易形成金属间化合物等复杂相,因而会使合金的性能恶化并使合金元素作用的分析变得困难。高熵合金作为了一种新型合金,突破了传统合金的设计理念,采用五种或五种以上元素按照等摩尔比或近等摩尔比进行混合而成,提高合金混合熵,促进固溶体的形成,有时会形成金属间化合物,甚至是非晶相,强化合金性能。本文选用Al、Fe、Ti、Cr、Ni、Zr、W、Mo和Nb九种元素中的几种元素按等摩尔比来配置合金,利用非自耗电弧熔炼炉熔炼,熔炼了FeTiNbMo W、FeCr NiMo NbW、FeTiCrNiMoNbW、AlFeCrNiMo NbW和TiZr Mo NbW五种高熵合金,采用SEM、EDS及XRD等方法对高熵合金进行组织形貌、相结构进行了分析,并分别对合金的密度,宏观、微观及退火的硬度及压缩性能进行测试。实验结果表明:FeTiCrNiMoNbW和TiZrMo NbW高熵合金形成了简单固溶体结构,其他几种合金均由简单固溶体和金属间化合物组成,FeTiNbMo W、FeCrNiMo NbW、FeTiCrNiMoNbW和AlFeCrNiMo NbW高熵合金的组织形貌均为典型的树枝晶形貌,而TiZr Mo NbW高熵合金为棉絮状组织。五种高熵合金的实测密度均大于理论密度,且高熵合金的洛氏硬度在HRC 54.5~HRC 66.8之间,树枝晶的显微硬度大于枝晶间,棉絮组织硬度大于棉絮间,合金的退火硬度均高于其铸态硬度,其中FeTiCr NiMo NbW和AlFeCrNiMo NbW合金在1200℃出现了退火软化现象。五种合金压缩强度在563.35MPa~2426.91MPa之间,断裂形式均为解理断裂,其中TiZrMo NbW高熵合金的性能做好。
[Abstract]:Traditional alloy systems are dominated by one or two elements, and the properties of alloys are restricted by the principal elements, and the traditional alloy design concept holds that the more principal components in the alloy system, the easier it is to form complex phases such as intermetallic compounds. As a result, the properties of the alloy will deteriorate and the analysis of the effect of the alloy elements will be difficult. As a new type of alloy, high entropy alloy has broken through the design idea of traditional alloy. Five or more elements are mixed according to equal molar ratio or near equal molar ratio to improve the mixing entropy of alloy and promote the formation of solid solution. Sometimes intermetallic compounds, even amorphous phases, are formed to strengthen the properties of the alloy. In this paper, five kinds of high entropy alloys, FeTiNbMo Wy FeCr NiMo NbW,FeTiCrNiMoNbW,AlFeCrNiMo NbW and TiZr Mo NbW, are melted in non-consumable arc melting furnace by using several elements of Al,Fe,Ti,Cr,Ni,Zr,W,Mo and Nb in equal molar ratio. The microstructure and phase structure of the high entropy alloy were analyzed by SEM,EDS and XRD. The hardness and compressive properties of the alloy were tested by means of density, macroscopical, microcosmic and annealed. The experimental results show that FeTiCrNiMoNbW and TiZrMo NbW high entropy alloys form a simple solid solution structure, and the other alloys are composed of simple solid solution and intermetallic compounds. The microstructure of both FeTiNbMo WGuFeCrNiMo NbW,FeTiCrNiMoNbW and AlFeCrNiMo NbW high entropy alloys are typical dendritic morphology. TiZr Mo NbW high entropy alloy is cotton-like structure. The measured densities of the five kinds of high entropy alloys are all higher than the theoretical densities, and the Rockwell hardness of the high entropy alloys is in the range of HRC 54.5~HRC 66. 8, the microhardness of dendrite is greater than that of dendrite, and the microhardness of cotton flocs is greater than that of cotton floc. The annealed hardness of the alloy is higher than that of the as-cast alloy, and FeTiCr NiMo NbW and AlFeCrNiMo NbW alloys show annealing softening phenomenon at 1200 鈩，

本文编号：2213623