Al_(11.5)Cr_(16)Fe_(17)Ni_(51.5)V_(4)高熵合金中L1_(2)结构纳米共格相的析出行为及其对力学性能的影响  

Precipitation behavior of coherent nanoscale phase with L1_(2) structure and its effect on mechanical properties of Al_(11.5)Cr_(16)Fe_(17)Ni_(51.5)V_(4) high-entropy alloy

作　　者：印家辉 林耀军 Yin Jiahui;Lin Yaojun(School of Materials Science and Engineering,Wuhan University of Technology,Wuhan Hubei 430070,China)

机构地区：[1]武汉理工大学材料科学与工程学院,湖北武汉430070

出　　处：《金属热处理》2024年第11期29-37,共9页Heat Treatment of Metals

摘　　要：以Al_(11.5)Cr_(16)Fe_(17)Ni_(51.5)V_(4)高熵合金为研究对象,研究了固溶处理成单相固溶体的该合金在600℃时效不同时间后的微观组织和拉伸性能。结果表明,经1150℃保温7 min再结晶退火/固溶处理后,该合金组织为单相FCC固溶体。600℃时效处理后,形成了具有L1_(2)结构的纳米尺寸球状富Ni、Al元素的γ′-Ni_(3)Al析出相。随时效时间延长,γ′析出相的尺寸和体积分数单调增加,晶粒尺寸轻微长大。合金的屈服强度从306 MPa增加到863 MPa,抗拉强度从560 MPa增加到1272 MPa,同时合金保持了良好的韧性(均匀延伸率34.1%~17.7%)。时效过程中,合金强度的增加,主要归因于γ′相的析出强化,其析出强化的机制为位错切过机制。γ′相析出强化效应随γ′相尺寸和体积分数的增加而增加。合金的良好韧性取决于γ′析出相的共格特征和极小的纳米尺寸,降低了析出相/基体界面的应力集中。Selecting Al_(11.5)Cr_(16)Fe_(17)Ni_(51.5)V_(4) high-entropy alloy as the research object,the microstructure and tensile properties of the alloy with single-phase solid solution treated by solution treatment were studied after aging at 600℃for different time.The results show that the microstructure of the alloy is single-phase FCC solid solution after recrystallization annealing/solution treatment at 1150℃for 7 min.After aging at 600℃,nano-sized spherical Ni-rich and Al-richγ′-Ni_(3)Al precipitates with L1_(2) structure are formed.With the increase of aging time,the size and volume fraction of the precipitatedγ′phase increase monotonously,and the grain size increases slightly.The yield strength of the alloy increases from 306 MPa to 863 MPa,the tensile strength increases from 560 MPa to 1272 MPa,and the alloy maintains good toughness(uniform elongation of 34.1%-17.7%).During aging,the increase of strength is mainly attributed to the precipitation strengthening of theγ′phase,where the mechanism is the dislocation cutting.Theγ′precipitation strengthening effect increases with the increase of size and volume fraction of the precipitatedγ′phase.The good toughness of the alloy depends on the coherent characteristics of the precipitatedγ′phase and the extremely small nano-size,which reduces the stress concentration at the precipitated phase/matrix interface.

关 键 词：高熵合金 时效处理 析出强化 L1_(2)结构γ′析出相 力学性能 

分 类 号：TG146[一般工业技术—材料科学与工程]