王昌
,
徐海峰
,
黄崇湘
,
曹文全
,
董瀚
钢铁研究学报
doi:10.13228/j.boyuan.issn1001-0963.20150301
采用 SEM、TEM、STEM、XRD、EBSD 等实验分析方法对中锰钢(0.2C5Mn)在奥氏体逆相变不同时间退火过程中的微观组织演变进行了分析.结果表明：中锰钢在650℃短时间逆相变退火时析出大量 M3 C 型碳化物,随着退火时间的延长,逆相变奥氏体形成长大,获得马氏体、奥氏体双相片层状组织.马氏体与逆相变奥氏体晶粒取向服从 K-S 关系,且两相板条平均宽度在0.5μm 左右.退火过程中锰元素出现由淬火组织平均分布逐渐向逆相变奥氏体富集的配分行为,长时间退火后形成体积分数为30％的逆相变奥氏体,抗拉强度为960 MPa,屈服强度为500 MPa,总伸长率为40％,强塑积高达38.4 GPa??％.
关键词:
中锰钢
,
奥氏体
,
逆相变退火
,
锰配分
,
K-S 关系
,
STEM
张子旸
,
张宝林
,
周天明
,
蒋红
,
金亿鑫
,
李树玮
,
功能材料
报道了用STEM(扫描透射电子显微镜)对GaIn-AsSb/GaSb异质结的截面不同部分进行分析和研究的初步结果.STEM图像表明,在四元合金GaInAsSb与衬底GaSb的晶格常数不相同时,将会由于晶格的不匹配而产生失配位错和层错,这些缺陷是对应力的一种释放形式,包括60°位错、90°位错和堆垛层错,并且发现只有90°位错才会在外延层表面产生脊.
关键词:
GaInAsSb
,
位错
,
层错
,
STEM
Zhijun LIN
,
Meishuan LI
,
Yanchun ZHOU
,
null
,
null
材料科学技术（英文）
Layered ternary ceramics represent a new class of solids that combine the merits of both metals and ceramics. These unique properties are strongly related to their layered crystal structures and microstructures. The combination of atomic-resolution Z-contrast scanning transmission electron microscopy (STEM) and transmission electron microscopy (TEM), selected area electron diffraction (SAED), convergent beam electron diffraction (CBED) represents a powerful method to link microstructures of materials to macroscopic properties, allowing layered ternary ceramics to be investigated in an unprecedented detail. Microstructural information obtained using TEM is useful in understanding the formation mechanism, layered stacking characteristics, and defect structures for layered ternary ceramics down to atomic-scale level; and thus provides insight into understanding the ``Processing-Structure-Property" relationship of layered ternary ceramics. Transmission electron microscopic characterizations of layered ternary ceramics in Ti-Si-C, Ti-Al-C, Cr-Al-C, Zr-Al-C, Ta-Al-C and Ti-Al-N systems are reviewed.
关键词:
Layered ternary ceramics
,
ternary
,
ceramics
,
MAX
,
phase
,
TEM
,
S
Kinga Rodak
材料科学技术（英文）
The results presented in this study were concerned with microstructures and mechanical properties of polycrystalline Cu subjected to plastic deformation by a compression with oscillatory torsion process. Different deformation parameters of the compression with oscillatory torsion process were adopted to study their effects on the microstructure and mechanical properties. The deformed microstructure was characterized quantitatively by electron backscattered diffraction (EBSD) and scanning transmission electron microscopy (STEM). Mechanical properties were determined on an MTS QTest/10 machine equipped with digital image correlation. From the experimental results, processes performed at high compression speed and high torsion frequency are ecommended for refining the grain size. The size of structure elements, such as average grain size (D) and subgrain size (d), reached 0.42 μm and 0.30 μm, respectively, and the fraction of high angle boundaries was 35% when the sample was deformed at a torsion frequency f =1.6 Hz and compression rate v =0.04 mm/s. These deformation parameters led to an improvement in the strength properties. The material exhibited an ultimate tensile strength (UTS) of 434 MPa and a yield strength (YS) of 418 MPa. These values were about two times greater than those of the initial state.
关键词:
Severe plastic deformation
