摘要
目的研究轧制变形后不同温度退火处理对合金组织结构和力学性能的影响,揭示轧制及热处理对双相高熵合金的强化机制。方法利用XRD、SEM、EDS及EBSD表征合金组织结构,采用拉伸机及纳米压痕仪对合金进行力学特性测试。结果铸态合金呈现FCC+σ组织结构,轧制90%后,σ相衍射峰强度显著减弱,在800℃退火后增强;不同温度退火处理后合金显微组织变化过程如下:700℃回复阶段完成,900℃再结晶过程结束,1000℃再结晶晶粒长大。合金的显微硬度在轧制变形后升高,之后随退火温度的升高而逐渐降低,纳米压痕载荷-深度曲线及硬度值也符合此趋势;纳米压痕硬度点阵分布与合金显微组织变化一致;不同温度退火处理后,合金抗拉强度逐渐降低,断后伸长率逐渐升高,其中900℃退火后,合金的强塑性匹配最佳,其抗拉强度达873.4 MPa,断后伸长率保持12.8%。结论与铸态合金相比,CR90+900℃退火1 h的工艺参数可改善合金强塑性匹配关系,并使其强化机制转变为以细晶强化为主。
The work aims to study the influence of different annealing temperatures after rolling deformation on microstructure and mechanical properties of high-entropy alloys,and reveal the strengthening mechanisms of rolling and heat-treatment on dual-phase high-entropy alloys.The microstructure of alloys was characterized by XRD(X-ray Diffraction),SEM(Scanning Electron Microscopy),EDS(Energy Dispersive Spectroscopy),and EBSD(Electron Backscatter Diffraction).The mechanical properties were tested with a tensile testing machine and a nanoindentation tester.The results showed that:As-cast alloys exhibited an FCC(Face-Centered Cubic)+σphase microstructure.The diffraction peak intensity of theσphase decreased significantly,while it increased following annealing at 800℃after 90%rolling deformation.After annealing at different temperatures,the microstructure evolution process of alloys was as follows:the recovery stage was completed at 700℃,the recrystallization process was concluded at 900℃,and the recrystallized grains grew at 1000℃.The microhardness of alloys increased after rolling deformation and decreased gradually as the annealing temperature rose.The variation trends of nanoindentation load-depth curves and hardness values were consistent with this.The array distribution of nanoindentation hardness was consistent with the microstructural evolution of alloys.After annealing at different temperatures,the tensile strength of alloys decreased gradually,while the elongation after fracture increased progressively.Among them,alloys annealed at 900℃ exhibited the optimal strength-plasticity matching,with a tensile strength of 873.4 MPa and an elongation after fracture of 12.8%.Compared with as-cast alloys,the process parameters of CR90 and annealing at 900℃ for 1 h can improve the strength-plasticity matching relationship of alloys and transform the strengthening mechanism into one dominated by fine grain strengthening.
作者
韩春霞
吴亚楠
刘志宇
刘景顺
HAN Chunxia;WU Ya'nan;LIU Zhiyu;LIU Jingshun(School of Materials Science and Engineering,Inner Mongolia University of Technology,Hohhot 010051,China)
出处
《精密成形工程》
北大核心
2025年第12期25-34,共10页
Journal of Netshape Forming Engineering
基金
内蒙古自治区高等学校“创新团队发展计划”(NMGIRT2211)
内蒙古自治区一流学科科研专项项目(YLXKZX-NGD-002)。
关键词
高熵合金
轧制变形
退火温度
组织结构
力学性能
纳米压痕
high-entropy alloys(HEAs)
rolling deformation
annealing temperature
microstructure
mechanical properties
nanoindentation
