预变形对Al−Mg−Si−Cu合金析出相结构和形成机制的影响

• 作 者: 翁瑶瑶 贾志宏 丁立鹏 廖琎 张萍萍 徐亚琪 刘庆
• 机 构: 南京工程学院 材料科学与工程学院,南京 211167;南京工程学院 江苏省先进结构材料与应用技术重点实验室,南京 211167;南京工业大学 先进轻质高性能材料研究中心,南京 211816;重庆大学
• 出 处: 中国有色金属学报（英文版）
• 发表日期: 2022年2期
• 关键词: Al?Mg?Si?Cu alloy pre-straining Cu segregation precipitate HAADF-STEM

基于原子分辨率的高角环形暗场扫描透射电子显微镜(HAADF-STEM)系统研究预变形对Al?Mg?Si?Cu合金中析出相结构和形成机制的影响.在预变形合金中,沿位错处形成拉长和线状的析出相.在位错处形成的析出相具有以下3个特征:析出相内部呈非周期性原子排列;Cu原子偏聚发生在析出相/α(Al)的界面处;在一个析出相内部具有多种不同的取向.提出异质形核析出相的4种形成机制:被拉伸的析出相在位错上独立形成;线状析出相在位错上直接析出;不同的析出相相遇结合成线状析出相;析出相与其他相或溶质原子富集区相连接.这些不同的形成机制导致形成具有不同结构和形貌的析出相.“,”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.