A new insight on the diffusion growth mechanism of intermetallic compounds in Al-Er system

• Published in: Materials & design Vol. 224; p. 111341
• Main Authors: Tang, Zhichao, Cui, Jin, Yu, Muzhi, Zhu, Weiqiang, Xu, Zhengbing, Zeng, Jianmin, Xu, Tao, Yang, Haodong, Tan, Yapeng, Yang, Bo
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2022; Elsevier
• Subjects: Activation energy; Casting-cladding method; Diffusion; High-Temperature Laser-Scanning Confocal Microscopy (HTLSCM); Intermetallic compound (IMC); Parabolic growth constant (PGC); High-Temperature Laser-Scanning Confocal Microscopy (HTLSCM); Intermetallic compound (IMC); Parabolic growth constant (PGC); Diffusion; Casting-cladding method; Activation energy
• DOI: 10.1016/j.matdes.2022.111341
• ISSN: 0264-1275

[Display omitted] •During annealing, the growth characteristics of Al-Er intermetallic compounds are accord with layer-terraced growth.•In Al-Er system, AlEr grows by consuming Er component, the growth of Al3Er proceeds by swallowing AlEr.•The pre-exponential factor and activation energy of the Al3Er are 7.126 × 10−8 m2·s−1 and (88.4 ± 5.3) kJ·mol−1 respectively.•Al-Er diffusion couples were successfully prepared by casting cladding in the atmosphere. The diffusion growth of intermetallic compounds in Al-Er alloys are closely related to the properties of the alloys. The current work aims at explaining the dominance of Al3Er in the Al-Er alloys precipitation phases and the interface thin layer phenomenon by diffusion couple technique, estimating the parabolic growth constant and diffusion activation energy of intermetallic compound in Al-Er diffusion couples to provide theoretical guidance for the design of new Al-Er alloys. In this work, Al-Er diffusion couples were successfully prepared by casting-cladding method in the atmosphere. The growth of Al-Er intermetallic compounds at diffusion couple interface during annealing were observed and recorded by High-Temperature Laser-Scanning Confocal Microscopy at 673, 698, 723 and 748 K respectively. The results show that the growth characteristics of Al-Er intermetallic compounds were accord with layer-terraced growth during annealing. The thickness of intermetallic compound was linear with the square root of time at experimental temperature. The intermetallic compound layer was composed of Al3Er and a very thin AlEr phase. The parabolic growth constants of Al3Er phase at 673, 698, 723 and 748 K were 1.017 × 10−14, 1.609 × 10−14, 3.111 × 10−14 and 4.76 × 10−14 respectively. The activation energy of Al3Er phase was (88.4 ± 5.3) kJ/mol and the pre-exponential factor was 7.126 × 10−8 m2/s.