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- Lin, Danyang, et al.
(author)
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A Si-containing FeCoCrNi high-entropy alloy with high strength and ductility synthesized in situ via selective laser melting
- 2020
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In: Additive Manufacturing. - : Elsevier. - 2214-8604 .- 2214-7810. ; 35
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Journal article (peer-reviewed)abstract
- To widen the applications of new materials in additive manufacturing (AM), the traditional method of printing using pre-alloyed powders should be improved because the pre-alloying process is expensive and makes it difficult to adjust the composition of new materials. This study investigates the synthesis of a FeCoCrNi high-entropy alloy (HEA) containing 1.5 at.% Si in situ using selective laser melting (SLM). A remelting strategy and process optimization based on polynomial regression modeling allowed for the printing of almost fully dense (99.78 %) samples. The samples comprised columnar grains, each containing numerous subgrains of a single-phase face-centered cubic solid solution. No precipitation or segregation were observed. The room temperature tensile properties of the samples were excellent, with yields and tensile strengths reaching 701 +/- 14 and 907 +/- 25 MPa, respectively, and an elongation at fracture of 30.8 +/- 2%. These properties were attributed to solid solution strengthening and novel dislocation loop strengthening mechanism. These findings demonstrate that HEAs with a high relative density and good mechanical properties can be directly synthesized by SLM using inexpensive pure metal powders, thereby extending the application potential of AM to manufacture new materials.
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