• PDF / 4,536,536 Bytes
• 20 Pages / 593.972 x 792 pts Page_size
• 89 Downloads / 266 Views

DOWNLOAD

REPORT

---

Design and Tailoring of Alloys for Additive Manufacturing T.M. POLLOCK, A.J. CLARKE, and S.S. BABU Additive manufacturing (AM) promises a major transformation for manufacturing of metallic components for aerospace, medical, nuclear, and energy applications. This perspective paper addresses some of the opportunities for alloy and feedstock design to achieve site-specific and enhanced properties not attainable by conventional manufacturing processes. This paper provides a brief overview of the role of powders, as well as solidification and solid-state phase transformation phenomena typically encountered during fusion-based AM. Three case studies are discussed that leverage the above to arrive at microstructure control. The first case study focuses on approaches to modify the solidification characteristics by in-situ alloying. The second case study focuses on the need for concurrent design of alloys and processing conditions to arrive at the columnar to equiaxed transition during solidification. The third case study focuses on the design of a cobalt alloy for AM, with emphasis on tailoring liquid and solid state phase transformations. The need for comprehensive knowledge of processing conditions during AM, in-situ and ex-situ probing of microstructure development under AM conditions, and post-print processing, characterization, and qualification are articulated for the design of future alloys and component geometries built by AM. https://doi.org/10.1007/s11661-020-06009-3  The Minerals, Metals & Materials Society and ASM International 2020

I.

INTRODUCTION

ADDITIVE manufacturing (AM) offers a broad suite of new opportunities for the design and production of metallic components, particularly for the aerospace, energy, and biomedical sectors, where component geometry is complex and production volumes are low to moderate.[2] Furthermore, emerging print technologies offer the possibilities of on-demand manufacturing, customization, design complexities, part count reduction, reduction in lead time tooling and associated speedup in development, more efficient use of material, and energy and environmental benefits in terms of CO2 reduction.[3–8] In recent years, there have been significant advances in the design and production of metallic 3D printing systems[2–6] that use either wire or powder as input stock with conventional alloys. With these advances in machines, it is indeed possible to replace [1]

T.M. POLLOCK is with the University of California Santa Barbara, Santa Barbara, CA 93106. A.J. CLARKE is with the Colorado School of Mines, Golden, CO 80401. Contact e-mail: [email protected] S.S. BABU is with the The University of Tennessee, Knoxville, TN 37996 and also with the Oak Ridge National Laboratory, Oak Ridge, TN 37831. Manuscript submitted April 22, 2020.

METALLURGICAL AND MATERIALS TRANSACTIONS A

existing manufacturing processes, such as casting, with AM for low-volume, high-value added and geometrically complex components. While there are many excellent studies that focus on the fundamentals of printing, heat treatme