时效Ni_(2)CoCr_(0.5)Si_(0.3)Al_(0.1)Ti_(0.1)中熵合金的力学行为和变形机理的研究  

A Study on the Mechanical Behavior and Deformation Mechanism of the Aged Ni_(2)CoCr_(0.5)Si_(0.3)Al_(0.1)Ti_(0.1) Medium Entropy Alloy

作　　者：罗顺辉 常慧 王强 张佳鑫[1,2] 张团卫 王志华 LUO Shunhui;CHANG Hui;WANG Qiang;ZHANG Jiaxin;ZHANG Tuanwei;WANG Zhihua(Institute of Applied Mechanics,College of Mechanical and Vehicle Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Key Laboratory of Material Strength and Structural Impact,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学机械与运载工程学院应用力学研究所,太原030024 [2]太原理工大学山西省材料强度与结构冲击重点实验室,太原030024

出　　处：《太原理工大学学报》2024年第3期465-473,共9页Journal of Taiyuan University of Technology

基　　金：国家自然科学基金资助项目(12102291,12225207,12072220);山西省科技创新人才领军团队(202204051002006);中央引导地方科技发展资金资助项目(YDZJSX2021B002)。

摘　　要：【目的】设计了一种新型的Ni_(2)CoCr_(0.5)Si_(0.3)Al_(0.1)Ti_(0.1)中熵合金。【方法】在非等原子比Ni-Co-Cr基体的中熵合金中加入微量的Si、Al和Ti元素,并且通过不同温度的时效热处理进一步引入弥散的共格L12相沉淀。【结果】结果表明,700℃时效后的Ni_(2)CoCr_(0.5)Si_(0.3)Al_(0.1)Ti_(0.1)中熵合金具有最优异的力学性能,其屈服强度为783MPa,极限抗拉强度为1252MPa,伸长率为41.6%;相比退火处理样品,经过700℃时效处理使得合金的屈服强度提升了310MPa.分析合金在700℃时效样品的初始微观结构,可以确定合金中不仅存在共格的L12相结构,还有微量的金属间化合物Ni16Ti6Si7相。同时,由于高轧制量的冷轧变形和短时间的退火处理,在初始结构中发现微量的层错、纳米层错网格、Lomer-cottrell锁和位错钉扎现象的存在。其几何必需位错在拉伸过程中呈现出均匀分布,主要的变形模式以滑移为主,且具有层错结构,并没有发现变形孪晶。【Purposes】A novel type of Ni_(2)CoCr_(0.5)Si_(0.3)Al_(0.1)Ti_(0.1) medium entropy alloy is designed in this work.【Methods】Trace amounts of Si,Al,and Ti elements are added to the nonequiatomic ratio NiCoCr-based medium entropy alloy,and dispersed coherent L12 phase precipitation is introduced through aging heat treatment at different temperatures.【Findings】The results show that the Ni_(2)CoCr_(0.5)Si_(0.3)Al_(0.1)Ti_(0.1) medium entropy alloy aged at 700℃has the best mechanical properties,with a yield strength of 783 MPa,an ultimate tensile of 1252 MPa,and an elongation of 41.6%. Compared with the annealed samples, the alloy after aging treatment is increasedin yield strength by 310 MPa. Further analysis of the initial microstructure of the alloyaged at 700 ℃ reveals the presence of coherent L12 phase structure and trace amount of intermetalliccompound Ni16Ti6Si7 phase. Meanwhile, because of the severe deformation through coldrolling and the short time of annealing treatment, trace stacking faults, nano stacking fault networks,Lomer-Cottrell locks, and dislocation pinning phenomena are found in the initial structure.The geometrically necessary dislocation exhibits a uniform distribution during the stretchingprocess, and the main deformation mode is dominated by dislocation slip with a stackingfault structure.

关 键 词：中熵合金 成分设计 时效处理 力学性能 析出强化 变形机理 

分 类 号：O341[理学—固体力学]