The effect of pre-straining on the structure and formation mechanism of precipitates in an Al−Mg−Si−Cu alloy was systematically investigated by atomic resolution high-angle annular dark-field scanning transmission ele...The effect of pre-straining on the structure and formation mechanism of precipitates in an Al−Mg−Si−Cu alloy was systematically investigated by atomic resolution high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM).Elongated and string-like precipitates are formed along the dislocations in the pre-strained Al−Mg−Si−Cu alloy.The precipitates formed along the dislocations exhibit three features:non-periodic atomic arrangement within the precipitate;Cu segregation occurring at the precipitate/α(Al)interface;different orientations presented in one individual precipitate.Four different formation mechanisms of these heterogeneous precipitates were proposed as follows:elongated precipitates are formed independently in the dislocation;string-like precipitates are formed directly along the dislocations;different precipitates encounter to form string-like precipitates;precipitates are connected by other phases or solute enrichment regions.These different formation mechanisms are responsible for forming different atomic structures and morphologies of precipitates.展开更多
基金the Natural Science Foundation of Jiangsu Province,China(No.BK20201035)the Talent Research Fund in Nanjing Institute of Technology,China(No.YKJ201957)+1 种基金the National Natural Science Foundation of China(Nos.51871035,52001159)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Nos.20KJB430016,20KJB430012).
文摘The effect of pre-straining on the structure and formation mechanism of precipitates in an Al−Mg−Si−Cu alloy was systematically investigated by atomic resolution high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM).Elongated and string-like precipitates are formed along the dislocations in the pre-strained Al−Mg−Si−Cu alloy.The precipitates formed along the dislocations exhibit three features:non-periodic atomic arrangement within the precipitate;Cu segregation occurring at the precipitate/α(Al)interface;different orientations presented in one individual precipitate.Four different formation mechanisms of these heterogeneous precipitates were proposed as follows:elongated precipitates are formed independently in the dislocation;string-like precipitates are formed directly along the dislocations;different precipitates encounter to form string-like precipitates;precipitates are connected by other phases or solute enrichment regions.These different formation mechanisms are responsible for forming different atomic structures and morphologies of precipitates.
