【作者】 李忠丽；

【导师】 孙宏飞；

【作者基本信息】 山东科技大学 ， 材料加工工程， 2010， 硕士

【摘要】 近年来,高熵合金的研究已成为材料研究的热点之一,它突破了以一种或两种元素为主元的合金设计,发展出一种新的合金设计理念。高熵合金是采用至少五种元素按照等摩尔比或近等摩尔比进行混合形成的合金。多主元的混合产生高熵效应,使得高熵合金具有简单的微结构。高熵合金在各个方面表现出良好的性能,引起科学界的广泛关注和积极探索。本文选用常见的Al、Fe、Cu、Co、Ni、Cr、Ti、V八种合金元素,采用真空电弧炉成功制备出AlFeCuCoCr、CuCoCrNiFe、AlFeCuCoNiCr、AlFeCuCoNiCrTi0.5、AlFeCoCrNi、AlFeCuNiCrV及AlFeCuCoNiCrTiV七种高熵合金样品。采用OM、SEM、XRD及TEM实验方法对高熵合金的显微组织、表面形貌、相结构及形成机理进行分析。并对合金的硬度、抗高温退火软化性能、热稳定性及耐腐蚀性能进行测试。得出结论如下：(1)本文所制备的高熵合金都形成了FCC、BCC或FCC+BCC固溶体,有少数有序固溶相的生成。(2)Al元素在合金中促进BCC结构相形成,提高合金的硬度和强度。本实验中不含Al元素的CuCoCrNiFe合金硬度较低,其它含Al元素的高熵合金都具有较高的硬度,其硬度值在700-1200HV之间。(3)Cu元素在枝晶间偏聚,对高熵合金的韧塑性起主要作用。在实际应用方面,可以通过Cu元素的增减来设计不同韧塑性需求的高熵合金。(4)高熵合金具有较好的抗800℃高温退火软化性能。其中CuCoCrNiFe、AlFeCuCoNiCr、AlFeCoCrNi、AlFeCuCoNiCrTiV高熵合金退火后硬度提高,具有析出硬化特性。(5)高熵合金具有良好的热稳定性能。(6)高熵合金具有优良的耐酸腐蚀性能,本实验中除了AlFeCuNiCrV合金,其余合金耐酸腐蚀性能都优于304不锈钢。更多还原

【Abstract】 High entropy alloys with multi-principal elements are a novel concept for alloy design, which breaks through the traditional alloy design on the base of one or two major alloy elements, and become one of the hot research topics in materials science and engineering. High entropy alloys are composed of at least five elements which have equal mole or near equal mole ratios. High entropy effects arising from the mixture of multi-principal elements promote the formation of simple microstructures in the alloys. High entropy alloys have aroused the scholar’s attention and enthusiastic exploration all over the world because of their good performances in many aspects.In this thesis, eight common elements Al、Fe、Cu、Co、Ni、Cr、Ti and V were selected and seven high entropy alloys AlFeCuCoCr、CuCoCrNiFe、AlFeCuCoNiCr、AlFeCuCoNiCrTi0.5、AlFeCoCrNi、AlFeCuNiCrV and AlFeCuCoNiCrTiV were prepared by vacuum arc funace. Their microstructures, surface morphologies, phase structures and formation mechanism were investigated. And their hardness, softening resistance after high temperature annealing, thermal properties and corrosion resistance were studied. The results are showing as followed:(1) All the seven high entropy alloys form into bcc or fcc or bcc+fcc structures, only a little ordered solid solution structures are observed.(2) Al element promotes the formation of bcc structure, which will increase the hardness and strength of high entropy alloys. Except CuCoCrNiFe high entropy alloy which is without Al element exhibits low hardness, all the others exhibit high hardness in the range from 700 HVto1200HV.(3) Cu element segregates in the interdendrite and plays a leading role in the(4) High entropy alloys perform good softening resistance after 800℃high temperature annealing, and CuCoCrNiFe、AlFeCuCoNiCr. AlFeCoCrNi、AlFeCuCoNiCrTiV alloys exhibit higher hardness because of their precipitation hardening properties.(5) High entropy alloys perform good thermostability properties.(6) High entropy alloys perform good corrosion resistance. Except AlFeCuNiCrV alloy, all the others have better corrosion resistance than the 304 stainless steel.更多还原