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.998 北京科技大学学报 第29卷 为真实晶粒的 (2)Fe3Al基合金在低应变量下，能发生晶界 文献[2一3]在Fe3Al基合金超塑性变形试样中 “弓弯”形核，但核心不易长大，在“弓弯”部分伴随着 主要观察到连续动态再结晶现象，而本工作在压缩 一定的晶格转动：在高应变量下，亚结构充分发展导 试样实验中在较小应变量条件下，观察到了晶界“弓 致一定程度的连续动态再结晶过程的发生，形成细 弯”形核现象，表明在F3Al基合金中能够发生一定 小晶粒 程度的不连续动态再结晶，其差别可能和应变途径 不同相关.从EBSD分析结果来看，虽然在局部高 参考文献 应变梯度区域发生了一定程度的连续动态再结晶过 [1]单爱党，林栋梁，陈明伟，等.大晶粒Fe3A!基合金的超塑性·金 属学报，1995,31B(1):35 程，但在严重变形的原始晶粒内部主要是以取向差 [2]Lin D.Lin T C.Shan A.et al.Superplasticity in large grained 较小的亚晶界分割的亚晶，这与文献[8]用TEM技 Fe3Al alloys.Intermetallics.1996.4:489 术观察的断裂应变为1.26的样品中观察到的变形 [3]Lin D L,Liu Y.Microstructural evolution and mechanisms of su- 组织内部存在大量的取向角很小的亚晶界的结果是 perplasticity in largegrained iron aluminides.Mater Sci Eng, 1999,268A.83 基本一致的 [4]Chu J P,Liu I M.Wu J H.et al.Superplastic deformation in 从上面的分析可以看出：本实验中，Fe3Al在低 coarse-grained Fe-27Al alloys.Mater Sci Eng.1998.258 A:236 应变量下能发生晶界“弓弯”形核现象，即发生了一 [5]Gao D C.Yang W Y.Huang X.et al.Superplastic deformation in 定程度的不连续动态再结晶，但动态再结晶核心不 a coarse-grained Fe3Al based alloy.Scripta Mater.2001.44:501 [6]Nieh T G.Wadsworth J.Microstructural characteristics and de- 易长大，随着应变量的增加，F3Al晶粒内动态回复 formation properties in superplastic intermetallics.Mater Sci Eng 持续进行，亚结构充分发展，导致连续动态再结晶的 1997.239/240A.88 发生，形成了一定数量的细晶，显然由于单向压缩 [7]Chu J P,Wu J H.Yasuda H Y,et al.Electron backscattered 变形的局限，在本实验中并未得到完全的连续动态 diffraction study on superplastic properties of coarsegrained Fe 再结晶组织 27at%Al.Intermetallics.2000.839 [8]Huang XX,Yang W Y.Sun Z Q.Enhanced ductility in coarse 3结论 grained Fe3Al alloys.Intermetallics.2004.12:1019 [9]Derby B,Ashby M F.On Dynamic Recrystallization.Scripta (I)本实验所用的Fe3A1基合金在变形温度为 etll.1987,21(6):879 850℃、应变速率为10-3.1条件下进行单轴压缩变 [10]Wusatow ska-Sarnek A M,Miura H.Sakai T.Nucleation and mi- crotexture development under dynamic recrystallization of cop- 形时能够发生一定程度的动态再结晶，当应变达到 per.Mater Sci Eng.2002.323 A:177 3.0时，动态再结晶过程还不完全 Microstructure evolution of a Fe3Al-based alloy with coarse initial grains deformed at elevated temperature WANG Fei,LI Longfei,YANG Wangyue,SUN Zuqing) 1)State Key Laboratory for Advanced Metals and Materials.University of Science and Technology Beijing,Beijing 100083.China 2)Materials Science and Engineering School.University of Science and Technology Beijing.Beijing 100083.China ABSTRACI The microstructure evolution of a Fe3Al-based alloy was investigated by uniaxial compression tests on a Gleeble 1500 hot simulation test machine at 850C and a strain rate of 103s1.The results indicated that under the present deformation conditions the dynamic recrystallization of the Fe3Al-based alloy occurred.At low strain,the nuclei of dynamic recrystallization formed by bulging of initial grain boundaries,i.e.discontinuous dynamic recrystallization occurred:but the growth of the nuclei became more difficult with increasing strain.At large strain,finer dynamic recrystallized grains formed by the process of continuous dynamic recrystallization. KEY WORDS Fe3Al-based alloys:dynamic recrystallization:bulging;dynamic recovery;substructure为真实晶粒的． 文献［2－3］在 Fe3Al 基合金超塑性变形试样中 主要观察到连续动态再结晶现象而本工作在压缩 试样实验中在较小应变量条件下观察到了晶界“弓 弯”形核现象表明在 Fe3Al 基合金中能够发生一定 程度的不连续动态再结晶其差别可能和应变途径 不同相关．从 EBSD 分析结果来看虽然在局部高 应变梯度区域发生了一定程度的连续动态再结晶过 程但在严重变形的原始晶粒内部主要是以取向差 较小的亚晶界分割的亚晶这与文献［8］用 TEM 技 术观察的断裂应变为1∙26的样品中观察到的变形 组织内部存在大量的取向角很小的亚晶界的结果是 基本一致的． 从上面的分析可以看出：本实验中Fe3Al 在低 应变量下能发生晶界“弓弯”形核现象即发生了一 定程度的不连续动态再结晶但动态再结晶核心不 易长大．随着应变量的增加Fe3Al 晶粒内动态回复 持续进行亚结构充分发展导致连续动态再结晶的 发生形成了一定数量的细晶．显然由于单向压缩 变形的局限在本实验中并未得到完全的连续动态 再结晶组织． 3 结论 （1）本实验所用的 Fe3Al 基合金在变形温度为 850℃、应变速率为10－3s －1条件下进行单轴压缩变 形时能够发生一定程度的动态再结晶．当应变达到 3∙0时动态再结晶过程还不完全． （2）Fe3Al 基合金在低应变量下能发生晶界 “弓弯”形核但核心不易长大在“弓弯”部分伴随着 一定的晶格转动；在高应变量下亚结构充分发展导 致一定程度的连续动态再结晶过程的发生形成细 小晶粒． 参 考 文 献 ［1］ 单爱党林栋梁陈明伟等．大晶粒 Fe3Al 基合金的超塑性．金 属学报199531B（1）：35 ［2］ Lin DLin T CShan Aet al．Superplasticity in large-grained Fe3Al alloys．Intermetallics19964：489 ［3］ Lin D LLiu Y．Microstructural evolution and mechanisms of superplasticity in large-grained iron aluminides．Mater Sci Eng 1999268A：83 ［4］ Chu J PLiu I MWu J Het al．Superplastic deformation in coarse-grained Fe－27Al alloys．Mater Sci Eng1998258A：236 ［5］ Gao D CYang W YHuang Xet al．Superplastic deformation in a coarse-grained Fe3Al based alloy．Scripta Mater200144：501 ［6］ Nieh T GWadsworth J．Microstructural characteristics and deformation properties in superplastic intermetallics．Mater Sci Eng 1997239／240A：88 ［7］ Chu J PWu J HYasuda H Yet al．Electron backscattered diffraction study on superplastic properties of coarse-grained Fe－ 27at％ Al．Intermetallics20008：39 ［8］ Huang X XYang W YSun Z Q．Enhanced ductility in coarse grained Fe3Al alloys．Intermetallics200412：1019 ［9］ Derby BAshby M F．On Dynamic Recrystallization．Scripta Metall198721（6）：879 ［10］ Wusatowska-Sarnek A MMiura HSakai T．Nucleation and microtexture development under dynamic recrystallization of copper．Mater Sci Eng2002323A：177 Microstructure evolution of a Fe3A-l based alloy with coarse initial grains deformed at elevated temperature WA NG Fei 1）LI Longfei 1）Y A NG Wangyue 2）SUN Zuqing 1） 1） State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing100083China 2） Materials Science and Engineering SchoolUniversity of Science and Technology BeijingBeijing100083China ABSTRACT The microstructure evolution of a Fe3A-l based alloy was investigated by uniaxial compression tests on a Gleeble1500hot simulation test machine at850℃ and a strain rate of10－3s －1．The results indicated that under the present deformation conditions the dynamic recrystallization of the Fe3A-l based alloy occurred．At low strainthe nuclei of dynamic recrystallization formed by bulging of initial grain boundariesi．e．discontinuous dynamic recrystallization occurred；but the growth of the nuclei became more difficult with increasing strain．At large strainfiner dynamic recrystallized grains formed by the process of continuous dynamic recrystallization． KEY WORDS Fe3A-l based alloys；dynamic recrystallization；bulging；dynamic recovery；substructure ·998· 北 京 科 技 大 学 学 报 第29卷