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采用机械合金化(MA)及热压烧结工艺制备纳米晶Fe3Al块体材料。采用X射线衍射、透射电镜、扫描电镜等对MA粉体及热压块体的相及显微组织进行分析,并对热压块体的力学性能及断口形貌进行了测试分析。结果表明:Fe72Al28混合粉在球磨过程中,Al逐渐溶入Fe中,形成Fe(Al)过饱和固溶体,纳米晶粉体的结构有序度较低。在1200℃,保温1h下真空热压烧结,Fe(Al)转变为有序的DO3-Fe3Al,同时发生晶粒长大。Fe3Al块体晶粒尺寸为40.1nm,相对密度大于96%,维氏硬度626.8 HV,三点弯曲强度985MPa;弯曲断口为脆性断口,但也呈现出一定韧性断裂特征。
Nanocrystalline Fe3Al bulk material was prepared by mechanical alloying (MA) and hot pressing sintering. The phase and microstructure of MA powder and hot-pressed block were analyzed by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The mechanical properties and fracture morphology of hot block were tested and analyzed. The results show that during the milling process, Al gradually dissolves into Fe to form Fe (Al) supersaturated solid solution, and the nanocrystalline powder has a low degree of order of structure. At 1200 ℃ for 1h, the samples were vacuum hot-pressed for sintering, and the Fe (Al) was transformed into ordered DO3-Fe3Al and grain growth took place simultaneously. The grain size of Fe3Al bulk is 40.1nm, the relative density is more than 96%, the Vicker’s hardness is 626.8 HV and the three-point bending strength is 985MPa. The bending fracture is a brittle fracture, but it also shows some ductile fracture characteristics.