TY - JOUR

T1 - Assessing Printability Maps in Additive Manufacturing of Metal Alloys

AU - Johnson, Luke

AU - Mahmoudi, Mohamad

AU - Zhang, Bing

AU - Seede, Raiyan

AU - Huang, Xueqin

AU - Maier, Janine Tatjana

AU - Maier, Hans Jürgen

AU - Karaman, Ibrahim

AU - Elwany, Alaa

AU - Arróyave, Raymundo

PY - 2019/9/1

Y1 - 2019/9/1

N2 - We propose a methodology for predicting the printability of an alloy, subject to laser powder bed fusion additive manufacturing. Regions in the process space associated with keyhole formation, balling, and lack of fusion are assumed to be strong functions of the geometry of the melt pool, which in turn is calculated for various combinations of laser power and scan speed via a Finite Element thermal model that incorporates a novel vaporization-based transition from surface to volumetric heating upon keyhole formation. Process maps established from the Finite Element simulations agree with experiments for a Ni-5wt.%Nb alloy and an equiatomic CoCrFeMnNi High Entropy Alloy and suggest a strong effect of chemistry on alloy printability. The printability maps resulting from the use of the simpler Eagar-Tsai model, on the other hand, are found to be in disagreement with experiments due to the oversimplification of this approach. Uncertainties in the printability maps were quantified via Monte Carlo sampling of a multivariate Gaussian Processes surrogate model trained on simulation outputs. The printability maps generated with the proposed method can be used in the selection—and potentially the design—of alloys best suited for Additive Manufacturing.

AB - We propose a methodology for predicting the printability of an alloy, subject to laser powder bed fusion additive manufacturing. Regions in the process space associated with keyhole formation, balling, and lack of fusion are assumed to be strong functions of the geometry of the melt pool, which in turn is calculated for various combinations of laser power and scan speed via a Finite Element thermal model that incorporates a novel vaporization-based transition from surface to volumetric heating upon keyhole formation. Process maps established from the Finite Element simulations agree with experiments for a Ni-5wt.%Nb alloy and an equiatomic CoCrFeMnNi High Entropy Alloy and suggest a strong effect of chemistry on alloy printability. The printability maps resulting from the use of the simpler Eagar-Tsai model, on the other hand, are found to be in disagreement with experiments due to the oversimplification of this approach. Uncertainties in the printability maps were quantified via Monte Carlo sampling of a multivariate Gaussian Processes surrogate model trained on simulation outputs. The printability maps generated with the proposed method can be used in the selection—and potentially the design—of alloys best suited for Additive Manufacturing.

KW - Engineering

KW - Printability

KW - Additive manufacturing

KW - High entropy alloys

KW - NiNb

KW - selective laser melting

UR - https://www.sciencedirect.com/science/article/abs/pii/S1359645419304355?via%3Dihub

U2 - 10.1016/j.actamat.2019.07.005

DO - 10.1016/j.actamat.2019.07.005

M3 - Journal articles

VL - 176

SP - 199

EP - 210

JO - Acta Materialia

JF - Acta Materialia

SN - 1359-6454

ER -