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对铝热法制备的添加质量分数为10%Cr的块体纳米晶Fe3Al材料进行600℃、800℃、1 000℃的8 h等温处理后,通过X射线衍射(XRD)、透射电子显微镜(TEM)和电子探针分析材料的晶体结构和平均晶粒尺寸.结果表明,等温处理前后,Fe3Al材料的晶体结构始终保持无序bcc结构.材料的平均晶粒尺寸随退火温度的升高先增大后减小.等温处理前,材料的平均晶粒尺寸为21 nm,经过600℃、800℃和1 000℃等温处理后平均晶粒尺寸分别为31.7 nm、27.3 nm和24.6 nm.通过弯曲和压缩实验研究了材料的机械性能.等温处理前后,材料均具有较大的塑性变形量.材料的屈服强度随等温处理温度的升高而略有增大,是传统微米晶Fe3Al材料的3倍左右.含10%Cr的Fe3Al材料经过8 h的600℃、800℃和1 000℃等温处理后,具有优异的热稳定性和更高的强度.
The bulk nanocrystalline Fe3Al with 10% Cr added by aluminothermic method was subjected to isothermal treatment at 600 ℃, 800 ℃ and 1000 ℃ for 8 h, and then characterized by X-ray diffraction (XRD), transmission electron microscopy ) And the electron probe were used to analyze the crystal structure and the average grain size.The results show that the crystal structure of the Fe3Al material keeps the disordered bcc structure before and after the isothermal treatment.The average grain size of the material increases first and then decreases with the increase of the annealing temperature The average grain size of the material before the isothermal treatment was 21 nm, and the average grain sizes were 31.7 nm, 27.3 nm and 24.6 nm after being isothermally treated at 600 ℃, 800 ℃ and 1000 ℃, respectively. Through the bending and compression experiments The mechanical properties of the material before and after the isothermal treatment, the material has a larger amount of plastic deformation.The yield strength of the material increases slightly with the increase of the isothermal treatment temperature, is about 3 times the traditional micron crystal Fe3Al material containing 10 The Fe3Al% Cr material has excellent thermal stability and higher strength after isothermal treatment at 600 ℃, 800 ℃ and 1000 ℃ for 8 h.