Atomic structure of the austenite-cementite interface of proeutectoid cementite plates
Atomic structure of the austenite-cementite interface of proeutectoid cementite plates
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DOI：
10.1080/01418619908214271
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发表时间：
1999-01-01
期刊：
影响因子：
--
通讯作者：
Spanos, G
中科院分区：
文献类型：
--
作者：
Howe, JM;Spanos, G
在先前的研究中，基于传统的透射电子显微镜和计算机辅助原子匹配研究，奥氏体中先共析铁素体片的原子惯习面（或平台面）被推断为（1（1）在棒3）（A）上平行于（101）（C）（其中下标A表示奥氏体，下标C表示奥氏体）。在本研究中，采用高分辨率透射电子显微镜（HRTEM），以直接确定的原子结构和原子惯习面的铁素体-奥氏体界面对应的宽面的铁素体板。使Fe-1.3重量%C-13重量%Mn合金在650 ° C下等温反应100秒，以形成嵌入完全残留奥氏体基体中的奥氏体板。高分辨透射电镜观测直接证实了前面的推论：首先，平行于（101）（C）的棒3）（A）上的（1（1））是原子水平的先共析铁素体片的平台面，其次，铁素体-奥氏体界面含有平行于[110]（A）线方向的[010]（C）的凸台，第三，突出部导致相对于平行于（1（1）在杆3上）（A）阶地平面的（101）C倾斜的斜方板的平均惯态平面。连接平行于（101）（C）阶地的相邻（1（1）在杆3上）（A）的壁架平面被确定为平行于（（1）在杆13上）（A）的（001）（C），因此不垂直于阶地平面。一个几乎垂直的边缘失配位错对与每个平台和平台。这些位错中的一个或两个将不得不爬升，以使这些壁架附近的奥氏体-奥氏体界面迁移。壁架是界面的固有特征，即在大多数情况下，它们不是由断层或其他缺陷与奥氏体-奥氏体界面的相交引起的。
In a previous investigation, the atomic habit plane (or terrace plane) of proeutectoid cementite plates in austenite was deduced to be (1 (1) over bar 3)(A)parallel to(101)(C) (where the subscript A indicates austenite and the subscript C cementite), based on conventional transmission electron microscopy and computer-aided atom matching studies. In the present study, high-resolution transmission electron microscopy (HRTEM) was employed in order to determine directly the atomic structure and atomic habit plane of the cementite-austenite interface corresponding to the broad faces of cementite plates. An Fe-1.3 wt%C-13 wt%Mn alloy was isothermally reacted at 650 degrees C for 100s in order to form cementite plates embedded in a completely retained austenite matrix. The HRTEM observations directly confirm the previous deductions that; firstly (1 (1) over bar 3)(A)parallel to(101)(C) is the terrace plane of proeutectoid cementite plates at the atomic level, secondly the cementite-austenite interfaces contain ledges with a [010](C)parallel to[110](A) line direction, and thirdly the ledges result in an average habit plane of the cementite plates that is inclined with respect to the (101)C parallel to(1 (1) over bar 3)(A) terrace plane. The ledge plane connecting adjacent (1 (1) over bar 3)(A)parallel to(101)(C) terraces was determined to be (001)(C)parallel to((1) over bar 13)(A) and thus is not orthogonal to the terrace plane. A nearly perpendicular pair of edge misfit dislocations is associated with each ledge and terrace. One or both of these dislocations would have to climb in order for the cementite-austenite interface in the vicinity of these ledges to migrate. The ledges are intrinsic features of the interface, that is in most cases they do not result from intersections of faults or other defects with the cementite-austenite interface.