Session: 03-01 Metals: Post Processing Topics

Paper Number: 88979

88979 - Metal Additive Manufacturing Produced Components With Significantly Improved Mechanical and Corrosion Resistance Properties Upon Chemical-Mechanical Polishing 

The demand for metal additive manufactured (AM) components is growing at an accelerated rate. AM is not just an ideal route to produce rapid and practical prototypes, but it has also opened the door to produce truly free-form components. However, AM-built components have an inherent problem; they have a high level of surface-related defects (SRD). The most common SRD often encountered on AM components include partially sintered/melted powder, v-notches, dross formation in the overhang areas, surface/near-surface porosity, lack of fusion, lack of penetration, and delamination. These defects usually make the components susceptible to poor mechanical performance, early failure, and comprised corrosion resistance. Consequently, post-processing and surface finishing operations of the AM-built components are necessary to obtain a functional part. However, due to the extreme complexity of the AM-produced parts, traditional post-processing surface finishing is not a viable option in many cases. Therefore, there is a latent need for surface finishing techniques capable of improving the surface texture of the AM-produced components while also improving their mechanical and corrosion resistance properties. In addition, due to the distinctive characteristics of AM surface textures and their difference based on their build angle and orientation in the powder bed, it is imperative to consider the "anatomy" of the surfaces to achieve their accurate characterization and optimization. This presentation will discuss in detail the unique surface features characteristics of AM components and the good practices that should be followed to characterize them based on their structure. The parameters affecting the surface texture during the building process and how to optimize them will also be discussed. Different examples of surface finishing techniques (post-processing)  employed to improve the surfaces texture of AM components will be discussed and compared. Techniques such as chemical milling, chemical-mechanical polishing, abrasive finishing, electropolishing, and machining will be discussed, highlighting the different types of surface textures they produce and their viability to be applied in internal cavities or highly complexed components. Correlation between surface texture parameters, such as Ra, Wa, Sa, Rv, etc., and mechanical and corrosion resistance properties will be described. High cycle fatigue results of AM-produced Ti-6Al-4V, 15-5PH, AlF357, AlSi10Mg, IN-625, IN-718, and GRCop-42 specimens will be examined before and after surface finishing. Finally, in this presentation, we will discuss how we are overcoming the challenge of producing significantly improved surface textures of AM components to meet the industry's standards. We will explain in detail how we are tackling the different types of surface texture features that characterize AM-built components. 
 

Presenting Author: Agustin Diaz REM Surface Engineering

Presenting Author Biography: Dr. Diaz has worked on the surface optimization of metal Additive Manufacturing (AM) components using chemical-mechanical polishing techniques for the last 8 years at REM Surface Engineering. During this time, Dr. Diaz has developed different processes to achieve defect-free surface finished AM-built components to display optimal performance under mechanical stress. Part of his research is focused on the study and characterization of the surface texture of AM components built by different techniques, primarily powder bed methods and blown powder direct energy deposition. Other research areas that Dr. Diaz has been involved in encompass the synthesis, intercalation, and surface modification of inorganic layered nanomaterials for various applications; including drug delivery, emulsion stabilizers, nano-surfactants, lubricants additives, fire retardants, catalysis, catalytic supports, among others. He has authored 28 peer-reviewed research papers, has over 1200 citations, various patents, and several books including two chapters on the surface texture characterization of metal AM components for the aerospace industry, and their implication on fatigue performance. Moreover, Dr. Diaz is very active on standard committees, professional organizations, and other broader impact activities. He is a member of the B46 Project Team 53- Surface Finish for Additive Manufacturing and B46/Project Team Pool. In addition, Dr. Diaz is the Co-Founder and Marketing Editor of the LatinX Can Podcast, a bi-weekly podcast series that talks to LatinX professionals while they share their experience about how they turned their professional dream into reality in USA. Relevant Awards: 80NSSC18P2192 NASA Phase I SBIR “Internal/External Surface Finishing of Additively Manufactured IN-625 Components”; 80NSSC19C0211 NASA Phase II SBIR “Internal/External Surface Finishing of Additively Manufactured IN-625 Components”; 80NSSC20C0080 NASA Phase III SBIR; FA864921P0815 Air Force Phase II SBIR “Internal/External Surface Finishing of Additively Manufactured Aluminum Components”.

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