Influence of build layout and orientation on microstructural characteristics of electron beam melted Alloy 718
Journal article, 2018

Effects of build layout and orientation consisting of (a) height from the build plate (Z-axis), (b) distance between samples, and (c) location in the build plate (X-Y plane) on porosity, NbC fraction, and hardness in electron beam melted (EBM) Alloy 718 were studied. The as-built samples predominantly showed columnar structure with strong < 001 > crystallographic orientation parallel to the build direction, as well as NbC and delta-phase in inter-dendrites and grain boundaries. These microstructural characteristics were correlated with the thermal history, specifically cooling rate, resulted from the build layout and orientation parameters. The hardness and NbC fraction of the samples increased around 6% and 116%, respectively, as the height increased from 2 to 45 mm. Moreover, by increasing the height, formation of delta-phase was also enhanced associated with lower cooling rate in the samples built with a greater distance from the build plate. However, the porosity fraction was unaffected. Increasing the sample gap from 2 to 10 mm did not change the NbC fraction and hardness; however, the porosity fraction increased by 94%. The sample location in the build chamber influenced the porosity fraction, particularly in interior and exterior areas of the build plate. The hardness and NbC fraction were not dependent on the sample location in the build chamber.

Microstructural characterization

Additive manufacturing

Hardness

Electron beam melting (EBM)

Alloy 718

Author

P. Karimi

University West

E. Sadeghi

University West

D. Deng

Linköping University

Hans Gruber

Chalmers, Industrial and Materials Science, Materials and manufacture

J. Andersson

University West

P. Nylen

University West

International Journal of Advanced Manufacturing Technology

0268-3768 (ISSN) 1433-3015 (eISSN)

Vol. 99 9-12 2903-2913

Subject Categories

Analytical Chemistry

Geochemistry

DOI

10.1007/s00170-018-2621-6

More information

Latest update

3/19/2019