摘要
目的获得高热稳定性的铁基高熵纳米合金并研究其热稳定性机理。方法通过高能球磨方法制备了Fe-Zr_(x)Nb_(x)Mo_(x)Ta_(x)(x=0.1、0.2、0.5、1,原子数分数)单相纳米合金粉末,在不同的退火处理温度下对退火前后的组织演变与元素偏析行为进行表征。结果获得了尺寸为15 nm的极细FeZr_(0.2)Nb_(0.2)Mo_(0.2)Ta_(0.2)晶粒,在900℃下退火1 h后,平均晶粒尺寸增长到73 nm,有第二相Fe_(2)Ta析出。而纳米晶Fe-Zr_(1.0)Nb_(1.0)Mo_(1.0)Ta_(1.0)合金在同样条件下退火后尺寸为55 nm,同时观察到Fe_(2)Ta和FeZr_(2)析出。结论高熵元素的加入使该类合金具有较好的热稳定性,而新强化相的析出进一步抑制了高温下的晶粒生长,即Fe-ZrNbMoTa合金在高温下的稳定性主要是受多组分偏析引起晶界处能量降低的热力学机制和与溶质拖拽、钉扎相关的动力学机制共同影响。
The work aims to obtain iron-based high entropy nanocrystalline alloy with enhanced thermal stability and study its thermal stability mechanism.Single-phase nanocrystalline Fe-Zr_(x)Nb_(x)Mo_(x)Ta_(x)(x=0.1,0.2,0.5,1.0,atomic number fraction)alloy powder was prepared by high energy ball milling.Its microstructure evolution and element segregation before and after annealing at different temperature were characterized subsequently.Ultra-fine Fe-Zr_(0.2)Nb_(0.2)Mo_(0.2)Ta_(0.2) grains of 15 nm were obtained.The average grain size increased to 73 nm after annealing at 900℃ for 10 h,and the second phase Fe2Ta was precipitated.The size of nanocrystalline Fe-ZR_(1.0)Nb_(1.0)Mo_(1.0)Ta_(1.0) alloy was 55 nm after annealing under the same conditions,and Fe_(2)Ta and FeZr_(2) were precipitated simultaneously.The addition of high entropy elements contributes to good thermal stability of the alloy.The precipitation of new enhanced phase further restrains the growth of grans at high temperature.Namely,the stability of Fe-ZrNbMoTa alloy at high temperature is mainly under the thermodynamic effect of grain boundary energy reduction caused by multicomponent segregation between elements as well as the dynamic effect relevant to solute drag and pinning.
作者
顾申翔宇
王晓巍
王振宇
王汝江
赵李新
陈正
GU Shen-xiang-yu;WANG Xiao-wei;WANG Zhen-yu;WANG Ru-jiang;ZHAO Li-xin;CHEN Zheng(College of Materials Science and Engineering,China University of Mining and Technology,Jiangsu Xuzhou 221008,China;AVIC Shenyang Aircraft Corporation,Shenyang 110850,China)
出处
《精密成形工程》
北大核心
2022年第8期42-47,共6页
Journal of Netshape Forming Engineering
基金
国家重点研发计划(2018YFB2001204)。
关键词
多组分纳米晶
热稳定性
共偏析
晶界能
multi-component nanocrystalline
thermal stability
co-segregation
grain boundary energy
