【摘要】 通过铝热反应法分别制备未加Si和加Si的块体纳米晶Fe-Al-Cr和Fe-Al-Mn材料。利用OM,XRD,EPMA和TEM对制得的材料进行微观组织观察。结果表明:加入质量分数为5%的Si之后,2种材料的平均晶粒尺寸变化不大;含10%Cr的材料晶体结构没有发生变化,均由无序bcc结构组成,而含15%Mn材料的晶体结构由之前的有序DO3结构向B2结构转变;Si元素的加入可降低Cr、Mn元素在Fe3Al中的溶解度,使基体中有Cr、Mn相析出。对材料进行硬度和应力应变曲线的测试,发现加入5%Si后,各材料的硬度均有较大程度的提高,塑性显著降低;含10%Cr的材料屈服强度由790 MPa减小至642 MPa,而含15%Mn的材料屈服强度由708 MPa增大至808 MPa。更多还原

【Abstract】 Bulk nanocrystalline Fe-Al-Cr and Fe-Al-Mn materials with and without Si element were prepared by aluminothermic reaction,respectively.Microstructures of the materials were investigated by optical microscope,electron probe microscope X-ray diffraction and transmission electron microscope.The results show that,after adding 5%Si(mass fraction,the same below),the average grain size of two materials have no obvious change;the crystal structure of materials with 15%Mn changed from DO3 to B2,while the materials with 10%Cr had no change;the addition of Si element results in the precipitation of phases containing Cr,Mn element in the materials.Hardness and compressive properties of the materials were also tested,which indicates that,after adding 5%Si element,the hardness of both materials increases sharply,and the plasticity of the materials reduced significantly;the yield strength of the material with 10%Cr dropped from 790 to 642 MPa,while the material with 15%Mn increased from 708 to 808 MPa.更多还原