The effects of material anisotropy on secondary processing of additively manufactured CoCrMo

• Published in: Additive manufacturing Vol. 29; no. C; p. 100764
• Main Authors: Fernandez-Zelaia, Patxi, Nguyen, Vinh, Zhang, Hayley, Kumar, Arkadeep, Melkote, Shreyes N.
• Format: Journal Article
• Language: English
• Published: United States Elsevier B.V 01.10.2019; Elsevier
• Subjects: Additive manufacturing; Anisotropy; Crystallography; Indentation; MATERIALS SCIENCE; Milling; Additive manufacturing; Anisotropy; Indentation; Crystallography; Milling
• ISSN: 2214-8604; 2214-7810
• DOI: 10.1016/j.addma.2019.06.015

Components produced by near net shape additive manufacturing processes often require subsequent subtractive finishing operations to satisfy requisite surface finish and geometric tolerances. It is well established that the microstructure and properties of the as-built component are sensitive to the additive processing history. Therefore, downstream secondary processes may be affected by the as-built components’ mechanical behavior. In this work we study the sensitivity of secondary machining operations on CoCrMo samples produced via laser powder bed fusion. Utilizing novel high-throughput mechanical testing, microstructure characterization, and a rigorous statistical analysis we investigate the degree of material anisotropy present in the as-built material. We then study the effects of this anisotropy on secondary processing via slot milling experiments. Our results indicate that mechanical anisotropy is driven by both the morphology of the microstructure as well as crystallographic texture. The machining force response is correspondingly sensitive to these sources of anisotropy, which has the potential to impact how manufacturers finish additively built parts.