Formation of denuded zones in crept Mg–2.5Gd–0.1Zr alloy
Formation of denuded zones in crept Mg–2.5Gd–0.1Zr alloy
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DOI：
10.1016/j.actamat.2014.10.046
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发表时间：
2015-02
期刊：
影响因子：
9.4
通讯作者：
Wen-Fan Xu;Y. Zhang;L. Peng;W. Ding;J. Nie
中科院分区：
文献类型：
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作者：
Wen-Fan Xu;Y. Zhang;L. Peng;W. Ding;J. Nie
使用电子背散射衍射和透射电子显微镜系统地研究了在 300 °C、40、60 和 80 MPa 下蠕变的 Mg–2.5Gd–0.1Zr (at.%) 合金中形成的裸露区。剥蚀区出现在与晶界相邻的基体区域中，晶界大致垂直于所施加的应力方向，并且它们主要在蠕变试验的第三蠕变阶段变宽。大多数剥蚀区的特征是在一侧分布有晶界颗粒阵列，并且剥蚀区和晶粒内部之间存在取向错误。取向错误是由剥蚀区和晶粒内部之间形成位错壁引起的，它导致该区域中原本共格的析出物与周围基体之间失去相干匹配，进而导致该区域中的析出物溶解，从而形成剥蚀区。
Denuded zones formed in a Mg–2.5Gd–0.1Zr (at.%) alloy crept under 40, 60 and 80 MPa at 300 °C are systematically studied using electron backscattered diffraction and transmission electron microscopy. The denuded zones are found in matrix regions adjacent to grain boundaries lying approximately perpendicular to the applied stress direction, and they widen mainly in the tertiary creep stage of the creep tests. The majority of the denuded zones are characterized by the distribution of an array of grain boundary particles on one side and a misorientation between the denuded zone and the grain interior. The misorientation is caused by the formation of a dislocation wall between the denuded zone and the grain interior, and it leads to a loss of coherent matching between the otherwise coherent precipitates and the surrounding matrix in this region, which in turn results in the dissolution of the precipitates in this region and hence the formation of a denuded zone.