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Effect of SLM Parameters on Transformation Temperatures of Shape Memory Nickel Titanium Parts[Note 2. P, v, h, and t correspond to laser power, ...]
Author(s) -
Dadbakhsh Sasan,
Speirs Mathew,
Kruth JeanPierre,
Schrooten Jan,
Luyten Jan,
Van Humbeeck Jan
Publication year - 2014
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201300558
Subject(s) - materials science , selective laser melting , nickel titanium , shape memory alloy , austenite , martensite , laser , laser power scaling , titanium , atmospheric temperature range , transformation (genetics) , metallurgy , diffusionless transformation , composite material , microstructure , thermodynamics , optics , biochemistry , physics , chemistry , gene
Selective laser melting (SLM) is used to manufacture dense nickel titanium (NiTi) parts. The reversible martensitic transformation of the NiTi parts is investigated with various SLM parameters. The parameters are in the same energy density range, composed of high laser parameters (HP: high laser power adjusted to high scanning speed) and low laser parameters (LP: low laser power adjusted to low scanning speed). The results are linked to the mechanical behavior and shape memory response achieved from compression and dilatometry tests. It is shown that the products may exhibit distinct transformation temperatures depending on the used SLM parameters. The atomized powders and the HP SLM parts with dominant pseudoelastic properties contain austenite at room temperature (due to their lower transformation temperatures), in contrast to the large thermal memory of the LP parts originating from martensitic phases (corresponding to higher transformation temperatures). The post‐annealed samples undergo transformations in a comparable temperature range, implying no significant effect of SLM on composition of the originally used powder. The possible origin of the above findings is postulated and discussed.