In Situ Structural Characterization of Ageing Kinetics in Aluminum Alloy 2024 across Angstrom-to-Micrometer Length Scales.
In Situ Structural Characterization of Ageing Kinetics in Aluminum Alloy 2024 across Angstrom-to-Micrometer Length Scales.
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DOI：
10.1016/j.actamat.2016.03.058
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发表时间：
2016-06
期刊：
影响因子：
9.4
通讯作者：
Ilavsky J
中科院分区：
文献类型：
--
作者：
Zhang F;Levine LE;Allen AJ;Campbell CE;Creuziger AA;Kazantseva N;Ilavsky J
采用非原位透射电子显微镜（TEM）和原位同步辐射超小角X射线散射、小角X射线散射（SAXS）相结合的方法研究了Al-Cu-Mg合金（AA 2024）在190 °C、208 °C和226 °C时效时的析出相结构和析出动力学。和横跨从亚埃到几微米的长度尺度的广角X射线散射（WAXS）。TEM带来的信息的性质，形态和尺寸的沉淀物，而SAXS和WAXS提供定性和定量的信息，在沉淀序列的不同阶段的沉淀物的随时间变化的尺寸和体积分数的演变。在实验时间分辨率内，这些老化温度下的沉淀涉及纳米尺寸小团簇的溶解和平面S相沉淀物的形成。使用三参数散射模型的基础上构建的TEM结果，我们建立了随温度变化的动力学团簇溶解和S相的形成过程同时进行。这两个过程被证明有不同的动力学速率，与集群溶解速率约两倍的S-相形成速率。我们确定了溶解活化能为（149.5 ± 14.6）kJ mol−1，即（1.55 ± 0.15）eV/atom，以及形成S沉淀的活化能为（129.2 ± 5.4）kJ mol−1，即（1.33 ± 0.06）eV/atom。重要的是，SAXS/WAXS结果表明，在实验老化条件下，样品中不存在中间的Guinier-Preston Bagaryatsky 2（GPB 2）/S″相。基于Langer-Schwartz理论和Kampmann-Wagner数值方法的降水模拟进一步验证了上述结果。
The precipitate structure and precipitation kinetics in an Al-Cu-Mg alloy (AA2024) aged at 190 °C, 208 °C, and 226 °C have been studied using ex situ Transmission Electron Microscopy (TEM) and in situ synchrotron-based, combined ultra-small angle X-ray scattering, small angle X-ray scattering (SAXS), and wide angle X-ray scattering (WAXS) across a length scale from sub-Angstrom to several micrometers. TEM brings information concerning the nature, morphology, and size of the precipitates while SAXS and WAXS provide qualitative and quantitative information concerning the time-dependent size and volume fraction evolution of the precipitates at different stages of the precipitation sequence. Within the experimental time resolution, precipitation at these ageing temperatures involves dissolution of nanometer-sized small clusters and formation of the planar S phase precipitates. Using a three-parameter scattering model constructed on the basis of TEM results, we established the temperature-dependent kinetics for the cluster-dissolution and S-phase formation processes simultaneously. These two processes are shown to have different kinetic rates, with the cluster-dissolution rate approximately double the S-phase formation rate. We identified a dissolution activation energy at (149.5 ± 14.6) kJ mol−1, which translates to (1.55 ± 0.15) eV/atom, as well as an activation energy for the formation of S precipitates at (129.2 ± 5.4) kJ mol−1, i.e. (1.33 ± 0.06) eV/atom. Importantly, the SAXS/WAXS results show the absence of an intermediate Guinier-Preston Bagaryatsky 2 (GPB2)/S″ phase in the samples under the experimental ageing conditions. These results are further validated by precipitation simulations that are based on Langer-Schwartz theory and a Kampmann-Wagner numerical method.
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影响因子：
9.4
作者：
Cheng, S.;Zhao, Y. H.;Ma, E.
通讯作者：
Ma, E.
影响因子：
9.4
作者：
Biswas, Aniruddha;Siegel, Donald J.;Seidman, David N.
通讯作者：
Seidman, David N.
影响因子：
9.4
作者：
Deschamps, A;Livet, F;Bréchet, Y
通讯作者：
Bréchet, Y
影响因子：
6
作者：
Abis, S;Massazza, M;Riontino, G
通讯作者：
Riontino, G
DOI：
10.1007/s11665-014-1255-6
发表时间：
2014-12-01
影响因子：
2.3
作者：
Chen, Qing;Wu, Kaisheng;Mason, Paul
通讯作者：
Mason, Paul