Abstract
Twinned Al-Mg alloys have been reported. However, the role of Mg solute in facilitating the formation of growth twins remains unclear. By using a precession-assisted crystal orientation mapping technique (PACOM) coupled with transmission electron microscopy (known as ASTAR), we examined the evolution of twin boundaries in Al, Al-1Mg, and Al-2.2Mg (at. %) films. The twinned grain fraction elevates with increasing film thickness until it reaches a peak when the film thickness is 120-160 nm. The Al-Mg alloys exhibited greater twinned grain fractions than pure Al. To investigate the fluctuation of twinned grain fraction, two types of twin boundaries were classified including intergranular and intragranular twins. The initial increase in twin density is attributed to the impingement of twinned grains during island coalescence and the twinned grains are more likely to survive during the grain growth process. Whereas the decrease in twinned grain fraction in thicker films is related to the removal of intragranular twins, and a lack of formation mechanisms of new twins.
Original language | English |
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Article number | 205301 |
Journal | Journal of Applied Physics |
Volume | 133 |
Issue number | 20 |
DOIs | |
State | Published - May 28 2023 |
Externally published | Yes |
Funding
This project is primarily funded by DoE-BES (Basic Energy Sciences) under Grant No. DE-SC0016337. The ASTAR crystal orientation system in a TEM microscope is supported by Office of Naval Research-Defense University Research Instrumentation Program (ONR-DURIP) under Award No. N00014-17-1-2921. Access to the Microscopy Facilities at Purdue University is also acknowledged. The authors also thank Dr. Sichuang Xue for discussions. This project is primarily funded by DoE-BES (Basic Energy Sciences) under Grant No. DE-SC0016337. The ASTAR crystal orientation system in a TEM microscope is supported by Office of Naval Research-Defense University Research Instrumentation Program (ONR-DURIP) under Award No. N00014-17-1-2921. Access to the Microscopy Facilities at Purdue University is also acknowledged. The authors also thank Dr. Sichuang Xue for discussions.