Er-modified AlSi7Mg alloy with high-density cellular structure and nano precipitates produced by selective laser melting

•Develop high-density cellular structure and nano phase through multiple thermal cycling.•Achieve transition toward equiaxed grains and efficient grain refinement by Er modification.•Clarify the mechanisms of coherent Al3Er precipitations on nucleation and grain refinement. The multiple thermal cycl...

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Bibliographic Details
Published in:Materials letters 2024-12, Vol.377, p.137446, Article 137446
Main Authors: Chen, Xi, Zhou, Qingbo, Pan, Yongfu, Leng, Jinfeng
Format: Article
Language:English
Subjects:
Additive manufacturing
Aluminum alloy
Cellular structure
Rapid solidification
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Summary:•Develop high-density cellular structure and nano phase through multiple thermal cycling.•Achieve transition toward equiaxed grains and efficient grain refinement by Er modification.•Clarify the mechanisms of coherent Al3Er precipitations on nucleation and grain refinement. The multiple thermal cycling processes during the selective laser melting (SLM) produce unique microstructure in AlSi7Mg alloy, and the Er-modification significantly affects the microstructure evolution under the thermal cycling. Due to the rapid solidification during the gas-atomization and SLM, the elements distribute uniformly in gas-atomized powder, and high-density cellular structure and nano precipitations form in as-built AlSi7Mg alloy. The Er-modification promotes the formation of coherent Al3Er nano particles through in-situ reaction, which act as the cores of heterogeneous nucleation and pin the subgrain boundaries, and result in higher fraction of fine equiaxed grains and substructure in Er-modified AlSi7Mg.
ISSN:0167-577X
DOI:10.1016/j.matlet.2024.137446