In-situ heating TEM observation of solidification cell evolutions in an Al-Fe alloy built by laser-powder bed fusion
Journal
Additive Manufacturing Letters
Journal Volume
11
Start Page
100251
ISSN
2772-3690
Date Issued
2024-12
Author(s)
DOI
10.1016/j.addlet.2024.100251
Abstract
Cellular structures (i.e., solidification cells) are a unique feature within alloys fabricated through rapid solidification, such as laser-powder bed fusion (L-PBF). Ever since the report of these structures’ beneficial effects on the material's mechanical properties, numerous studies have been devoted to the understanding of their formation mechanisms. Yet, the integrity and stability of the cellular structures are often less investigated, despite their significance on property interpretation and evolution. In this work, a stepwise in-situ heating transmission electron microscopy (TEM) experiment was performed on the exemplary LPBF-fabricated AlFeSiMoZr alloy. A critical threshold of 325 °C was identified, beyond which the cellular structures start to decompose in conjunction with precipitate coarsening. Preferred precipitate nucleation sites and their subsequent coarsening kinetics were determined and presented. Nanometer-sized crystalline embryos (3.81 ± 0.66 nm) were discovered within the cellular structure boundaries in their as-built condition, offering new insights on the precipitate formation and evolution at elevated temperatures.
Subjects
4D STEM
Al-Fe alloys
Al12(Fe
Mo)3Si
Cellular structures
Embryo
HRSTEM
In-situ heating TEM
Laser-powder bed fusion
Nucleation
Thermal stability
SDGs
Publisher
Elsevier BV
Type
journal article