Document Type

Article

Publication Date

5-2020

Publisher

Elsevier

Source Publication

Additive Manufacturing

Source ISSN

2214-7810

Abstract

WE43 is a high-strength, corrosion-resistant Mg-alloy containing rare earths such as Y and Nb, and has potential for many lightweight structural or bioresorbable prosthetic applications. In this study, additive manufacturing of dense WE43 alloy by laser powder bed fusion (LPBF) from gas atomized powders has been accomplished through studies involving single track scan of wrought WE43, parametric variation of LPBF, microstructural analysis and mechanical testing, both in compression and tension. The Archimedes method and image analyses from optical micrographs were employed to document the LPBF of dense (>99 % relative density) WE43 using optimum parameters of 200 W laser power, 1100 mm/sec scan speed, 0.13 mm hatch spacing, and 0.03 mm slice thickness. Moreover, the LPBF processing window for dense (>99 %) WE43 alloy was observed to exist for a range of power, 100 ∼ 250 W, using an energy density range of 32−37 J/mm3. The as-built microstructure consisted of fine (<10 μm) α-Mg (hcp) grains with globular -Mg3Nd precipitates and (Y,Zr)2O3 oxides. After the heat treatment, which consisted of solutionizing at 536 °C for 24 h and subsequent ageing at 205 °C for 48 h, the globular -Mg3Nd precipitates were observed to have dissolved and re-precipitate into thin sheets. The (Y,Zr)2O3 oxides were not found to dissolve or coalesce, but were agglomerated within α-Mg (hcp) matrix. Under compression, the as-built LPBF WE43 had, on average, yield strength of 224 MPa, compressive strength of 417 MPa and strain at failure of 9.5 %. In tension, the as-built LPBF WE43 had, on average, yield strength of 215 MPa, tensile strength of 251 MPa and strain at failure of 2.6 %. After the heat treatment, the LPBF WE43 had yield strength of 219 MPa, tensile strength of 251 MPa and strain at failure of 4.3 %. These values are comparable to those of WE43 design data specified by Magnesium Elektron.

Comments

Accepted version. Additive Manufacturing, Vol. 33 (May 2020): 101123. DOI. © 2020 Elsevier. Used with permission.

Le Zhou was affiliated with University of Central Florida at the time of publication.

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