Strategy for Texture Management in Metals Additive Manufacturing

• Published in: JOM (1989) Vol. 69; no. 3; pp. 523 - 531
• Main Authors: Kirka, M. M., Lee, Y., Greeley, D. A., Okello, A., Goin, M. J., Pearce, M. T., Dehoff, R. R.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.03.2017; Springer Nature B.V; Springer
• Subjects: Additive manufacturing; Chemistry/Food Science; Design; Earth Sciences; Engineering; Environment; Grain structure; Heat; Heat sources; Influence; MATERIALS SCIENCE; Mathematical models; Nickel base alloys; Physics; Raw materials; Strategy; Superalloys; Surface layer; Texture; Electron Beam Melting; Point Heat Source; Speed Function; Additive Manufacturing; Room Temperature Yield Strength
• ISSN: 1047-4838; 1543-1851
• DOI: 10.1007/s11837-017-2264-3

Additive manufacturing (AM) technologies have long been recognized for their ability to fabricate complex geometric components directly from models conceptualized through computers, allowing for complicated designs and assemblies to be fabricated at lower costs, with shorter time to market, and improved function. Lacking behind the design complexity aspect is the ability to fully exploit AM processes for control over texture within AM components. Currently, standard heat-fill strategies utilized in AM processes result in largely columnar grain structures. Proposed in this work is a point heat source fill for the electron beam melting (EBM) process through which the texture in AM materials can be controlled. Through this point heat source strategy, the ability to form either columnar or equiaxed grain structures upon solidification through changes in the process parameters associated with the point heat source fill is demonstrated for the nickel-base superalloy, Inconel 718. Mechanically, the material is demonstrated to exhibit either anisotropic properties for the columnar-grained material fabricated through using the standard raster scan of the EBM process or isotropic properties for the equiaxed material fabricated using the point heat source fill.