Al-Zn-Mg基合金多级时效不同热处理阶段的析出行为研
究
方磊;赵新奇;陈江华;刘吉梓;杨修波;刘萍;明文全;伍翠兰
【期刊名称】《电子显微学报》 【年(卷),期】2012(031)003
【摘要】The precipitation behaviors in a triple-step-aged AlZnMg alloy were studied using scanning transmission electron microscopy (STEM) , energy dispersive x-ray ( EDX) analysis, and x-ray diffraction in association with thermal treatments and hardness measurements. Results show that for one-step ageing higher hardness values can be achieved if the alloy is aged at 100 癈 rather than 120 X,. The retrogression, i.e. , the second step of the triple-step-ageing process, plays a crucial role in determining the precipitate microstructure of the alloy. It is demonstrated that if the retrogression temperature is in the range between 300 X. and 400 X. nearly all the precipitates formed in the first-step ageing are dissolved and further more will lead to more severe boundary segregation of solute atoms in the next step of re-ageing. However, the precipitate dissolution only destroys the precipitate structure and dissolves some of the solute atoms of the original precipitates. The remained solute atoms can form the solute cluster that would not re-transform back to original precipitate structures. As such the number of effective nuclei of the hardenning
Al-Zn-Mg基合金多级时效不同热处理阶段的析出行为研究
