In Situ Measurements of Melt-Pool Length and Cooling Rate During 3D Builds of the Metal AM-Bench Artifacts

This work provides results and analysis of the in situ thermal measurement acquired during the 3D builds performed for the 2018 additive manufacturing benchmark tests. The objective is to provide context for post-process characterization of distortion, residual strain, and microstructure, which are reported elsewhere in this Journal, and to provide validation data for thermal models of the build process. Four bridge artifacts (75 mm long, 5 mm wide, 12.5 mm tall) are created in each of three builds using a commercial laser powder bed fusion system. The builds are performed using nickel super alloy 625 (IN625). High-speed infrared thermography performed during four of the builds is used to measure the melt-pool length and cooling rate within a select region. The temperature of the substrate and build volume is measured during the fifth build to provide data to establish the boundary conditions for thermal models.

[1]  J. Beuth,et al.  Process Mapping of Inconel 625 in Laser Powder Bed Additive Manufacturing , 2015 .

[2]  Fan Zhang,et al.  Phase Fraction and Evolution of Additively Manufactured (AM) 15-5 Stainless Steel and Inconel 625 AM-Bench Artifacts , 2019, Integrating Materials and Manufacturing Innovation.

[3]  Pan Michaleris,et al.  3D spatial reconstruction of thermal characteristics in directed energy deposition through optical thermal imaging , 2015 .

[4]  Pan Michaleris,et al.  Experimental validation of finite element modeling for laser powder bed fusion deformation , 2016 .

[5]  M. E. Williams,et al.  Location-Specific Microstructure Characterization Within IN625 Additive Manufacturing Benchmark Test Artifacts , 2020, Integrating Materials and Manufacturing Innovation.

[6]  B. Lane,et al.  Calibration and Measurement Procedures for a High Magnification Thermal Camera , 2016 .

[7]  Pan Michaleris,et al.  Mitigation of distortion in large additive manufacturing parts , 2017 .

[8]  L. Levine,et al.  In Situ Thermography of the Metal Bridge Structures Fabricated for the 2018 Additive Manufacturing Benchmark Test Series (AM-Bench 2018) , 2020, Journal of Research of the National Institute of Standards and Technology.

[9]  Philip B. Prangnell,et al.  Effect of build geometry on the β-grain structure and texture in additive manufacture of Ti6Al4V by selective electron beam melting , 2013 .

[10]  Michael R. Hill,et al.  Elastic Residual Strain and Stress Measurements and Corresponding Part Deflections of 3D Additive Manufacturing Builds of IN625 AM-Bench Artifacts Using Neutron Diffraction, Synchrotron X-Ray Diffraction, and Contour Method , 2019, Integrating Materials and Manufacturing Innovation.

[11]  Brandon M. Lane,et al.  The effect of powder on cooling rate and melt pool length measurements using in situ thermographic techniques | NIST , 2017 .

[12]  Jack Beuth,et al.  Process Maps for Predicting Residual Stress and Melt Pool Size in the Laser-Based Fabrication of Thin-Walled Structures , 2007 .

[13]  T. Özel,et al.  Influence of scan strategy and process parameters on microstructure and its optimization in additively manufactured nickel alloy 625 via laser powder bed fusion , 2016, The International Journal of Advanced Manufacturing Technology.

[14]  T. Kunitomo,et al.  Study of the Radiative Properties of Heat Resisting Metals and Alloys : (1st Report, Optical Constants and Emissivities of Nickel, Cobalt and Chromium) , 1982 .

[15]  Tom Craeghs,et al.  Detection of Process Failures in Layerwise Laser Melting with Optical Process Monitoring , 2012 .

[16]  P. Michaleris,et al.  Residual stress and distortion modeling of electron beam direct manufacturing Ti-6Al-4V , 2015 .

[17]  Barry N. Taylor,et al.  Guidelines for Evaluating and Expressing the Uncertainty of Nist Measurement Results , 2017 .

[18]  P. Hooper.  Melt pool temperature and cooling rates in laser powder bed fusion , 2018, Additive Manufacturing.

[19]  VARIATION OF EMITTIVITY WITH POWDER BED FUSION BUILD PARAMETERS , 2016 .

[20]  Lyle Levine,et al.  Measurements of Melt Pool Geometry and Cooling Rates of Individual Laser Traces on IN625 Bare Plates , 2020, Integrating Materials and Manufacturing Innovation.

[21]  Kornel Ehmann,et al.  Cooling rate effect on tensile strength of laser deposited Inconel 718 , 2018 .

[22]  Measurement of Thermal Processing Variability in Powder Bed Fusion | NIST , 2018 .

[23]  Ryan R. Dehoff,et al.  Site specific control of crystallographic grain orientation through electron beam additive manufacturing , 2015 .

[24]  L. Levine,et al.  Coupled experimental and computational study of residual stresses in additively manufactured Ti-6Al-4V components , 2018, Materials Letters.

[25]  M. F. Zaeh,et al.  Thermography for Monitoring the Selective Laser Melting Process , 2012 .

[26]  Todd Palmer,et al.  Anisotropic tensile behavior of Ti-6Al-4V components fabricated with directed energy deposition additive manufacturing , 2015 .

[27]  Brandon M. Lane,et al.  Infrared thermography for laser-based powder bed fusion additive manufacturing processes , 2014 .

[28]  Shawn Moylan,et al.  Thermographic Measurements of the Commercial Laser Powder Bed Fusion Process at NIST. , 2015, Rapid prototyping journal.

[29]  J. M. Vitek,et al.  Correlation between solidification parameters and weld microstructures , 1989 .

[30]  J. Bunn,et al.  The Effect of Laser Scan Strategy on Distortion and Residual Stresses of Arches Made With Selective Laser Melting , 2016 .