新型增材制造FeCoNiAl中熵合金的时效硬化行为研究  

Study on Age Hardening Behavior of A Novel Additive ManufacturedFeCoNiAl Medium-Entropy Alloy

作　　者：韩欣洋 李相伟 廖伯凯 张友昭 郭兴蓬 王贝贝 张书彦 HAN Xinyang;LI Xiangwei;LIAO Bokai;ZHANG Youzhao;GUO Xingpeng;WANG Beibei;ZHANG Shuyan(Centre of Excellence for Advanced Materials,Dongguan 523808,China;School of Physics and Materials Science,Guangzhou University,Guangzhou 510006,China;School of Chemistry and Chemical Engineering,Guangzhou University,Guangzhou 510006,China)

机构地区：[1]东莞材料基因高等理工研究院,广东东莞523808 [2]广州大学物理与材料科学学院,广东广州510006 [3]广州大学化学化工学院,广东广州510006

出　　处：《热加工工艺》2024年第20期140-144,150,共6页Hot Working Technology

基　　金：广东省基础与应用基础研究重大项目(2020B0301030001);国家重点研发计划项目(2021YFB3702500);广东省基础与应用基础研究基金项目(2021A1515110061)。

摘　　要：FeCoNiAl系中熵合金因其独特的微观组织和优异的力学性能,具有广阔应用前景。采用选区激光熔化技术制备了一种新型FeCoNiAl中熵合金,研究时效温度对合金的微观组织与硬度的影响规律,揭示选区激光熔化成形FeCoNiAl中熵合金的强化机制。结果表明:打印态合金为单相BCC结构,硬度为31.2 HRC。时效处理后,在晶界和晶内析出大量纳米级的Ni3Al和Ni3Fe析出相。随着热处理温度逐渐提高,合金中的Ni3Fe相含量逐渐增加,合金的硬度呈现先升高后降低的趋势,在430℃/2 h时效处理后达到最高值44.3 HRC。继续提高时效温度到600℃后,Ni3Fe析出相由点状、针状变为粗大的树枝状,FCC相含量达到33.9%,合金时效硬度降低至31.9 HRC。热处理过程中纳米级Ni3Fe和Ni3Al相析出引起的析出强化是FeCoNiAl中熵合金硬度提高的主要原因。FeCoNiAl medium-entropy alloys(MEAs)have broad application prospects due to their unique microstructure and excellent mechanical properties.A novel FeCoNiAl MEA was manufactured by selective laser melting(SLM)technique.The effects of aging temperature on the microstructure and hardness of the alloy was studied.The strengthening mechanism of the FeCoNiAl MEA prepared by SLM was revealed.The results show that the as-built alloy is a single BCC phase structure with a hardness of 31.2 HRC.After aging treatment,a large number of nano-scale Ni3Al and Ni3Fe are precipitated in grain boundaries and grains.With the increase of the heat treatment temperature,the content of Ni3Fe phase in the alloy increases gradually,and the hardness of the alloy shows a trend of increasing first and then decreasing,and it reaches the highest value of 44.3 HRC after aging treatment at 430℃for 2 h.Increasing the aging temperature to 600℃,the Ni3Fe precipitates change from point-like and needle-like to coarse dendritic,the FCC phase content reaches 33.9%,and the aging hardness of the alloy decreases to 31.9 HRC.The precipitation strengthening caused by the precipitation of nano-scale Ni3Fe and Ni3Al during heat treatment is the main reason for the increase of hardness of the FeCoNiAl MEA.

关 键 词：选区激光熔化 中熵合金 时效处理 微观组织 洛氏硬度 

分 类 号：TG156[金属学及工艺—热处理] TG455[金属学及工艺—金属学]