Achieving the excellent intermediate-temperature strength-ductility synergy in a fine-grained FeCrNi-based medium entropy alloy with heterogeneous precipitation  

作　　者：Tianxiang Bai Tuanwei Zhang Zhiming Jiao Jinyao Ma Hui Chang Jianjun Wang Dan Zhao Shengguo Ma Zhouzhu Mao Xiaoxiao Liu Zhihua Wang 

机构地区：[1]Institute of Applied Mechanics,College of Mechanical and Vehicle Engineering,Taiyuan University of Technology,Taiyuan 030024,China [2]Shanxi Key Laboratory of Material Strength and Structural Impact,Taiyuan University of Technology,Taiyuan 030024,China [3]Instrumental Analysis Center,Taiyuan University of Technology,Taiyuan 030024,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2025年第5期1198-1207,共10页矿物冶金与材料学报(英文版)

基　　金：supported by the National Natural Science Foundation of China(Nos.12072220,12102291,and 12225207);the Science and Technology Innovation Teams of Shanxi Province,China(No.202204051002006);the Central Guidance on Local Science and Technology Development Fund of Shanxi Province,China(No.YDZJSX2021B002).

摘　　要：Fe-Cr-Ni austenitic alloys are extensively utilized in the hot-end components of nuclear light water reactors,turbine disks,and gas compressors.However,their low strength at elevated temperatures limits their engineering applications.In this study,a novel precipit-ation-strengthened alloy system is developed by incorporating Al and Si elements into a FeCrNi equiatomic alloy.The results indicate that the FeCrNiAl_(x)Si_(x)(at%,x=0.1,0.2)alloys possess heterogeneous precipitation structures that feature a micron-scaleσphase at the grain boundaries and a nanoscale ordered body-centered cube(B2)phase within the grains.An exceptional strength-ductility synergy across a wide temperature range is achieved in FeCrNiAl_(0.1)Si_(0.1)alloys due to grain refinement and precipitation strengthening.Notably,a yield strength of 693.83 MPa,an ultimate tensile strength of 817.55 MPa,and a uniform elongation of 18.27%are attained at 873 K.The dislo-cation shearing mechanism for B2 phases and the Orowan bypass mechanism forσphase,coupled with a high density of nano-twins and stacking faults in the matrix,contribute to the excellent mechanical properties at cryogenic and ambient temperatures.Moreover,the emergence of serratedσphase and micro-twins in the matrix plays a crucial role in the strengthening and toughening mechanisms at inter-mediate temperatures.This study offers a novel perspective and strategy for the development of precipitation-hardened Fe-Cr-Ni austen-itic alloys with exceptional strength-ductility synergy over a broad temperature range.

关 键 词：high/medium-entropy alloys medium temperature mechanical property serratedσphase 

分 类 号：TG139[一般工业技术—材料科学与工程]