退火对铝热反应制备的添加10%Cr的Fe_3Al材料晶粒尺寸和力学性能的影响(英文)

Effect of Annealing on Grain Size and Mechanical Properties of Bulk Nanocrystalline Fe_3 Al Material with 10%Cr Prepared by Aluminothermic Reaction

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.

Crystal structure and grain size of bulk nanocrystalline Fe3Al added with 10%（mass fraction） Cr,after annealing at 600 ℃,800 ℃ and 1 000 ℃ for 8 h,were investigated by X-ray diffraction（XRD）,transmission electron microscope（TEM） and electron probe microscope.Results show that the material had a disordered bcc structure of Fe3Al,which did not change with temperature.Average grain size of the material increased first and then decreased with the rise of annealing temperature,which was 21 nm before annealing and 31.7 nm,27.3 nm and 24.6 nm,respectively,after annealing at 600 ℃,800 ℃ and 1 000 ℃.Mechanical properties were investigated by bending and compressive tests.It was indicated that the material both before and after annealing had a considerable plastic deformation.Yield strength of the material increased slightly with the increase of elevated temperature,which was about three times higher than that of traditional microcrystalline Fe3Al material.The material with 10%（mass fraction） Cr after annealing at 600 ℃,800 ℃ and 1 000 ℃ for 8 h has good thermal stability and higher strength.