Additive Manufacturing Keynote Session: Additive Manufacturing Keynote Session
Sponsored by: TMS: Additive Manufacturing Committee
Program Organizers: Ryan Dehoff, Oak Ridge National Laboratory
Monday 2:30 PM
February 24, 2020
Room: 6A
Location: San Diego Convention Ctr
2:30 PM Introductory Comments
2:35 PM Keynote
Roles of Thermal Cycles in The Microstructure and Property Controls in Low-alloy High Strength Steels: Tadashi Furuhara1; 1Tohoku University
Development of additive manufacturing technology has broadened drastically the potentials for improving the properties of metallic materials. However, application of additive manufacturing in steels is still limited in high alloys such as stainless and maraging steels.During typical additive manufacturing processing, materials experience various rapid heating and cooling cycles, resulting in complex microstructure changes, similarly to multi-pass welding. It is known that application of sophisticated thermal cycles is very important in microstructure and properties in high strength steels. In this presentation, fundamentals of thermal cycles in grain refining, alloy partitioning during phase transformation and refining precipitation dispersion in low-alloy steels are briefly introduced and importance of thermal history will be emphasized in application of additive manufacturing to low alloy steels.
3:05 PM Keynote
Microstructural Control for Additive Manufacturing—An Advanced Microscopy Approach: Simon Ringer1; 1University of Sydney
AM is emerging as a gateway to unexplored metallurgical phenomena that must be understood to open the full potential of the technology in terms of cost, design-flexibility and design-complexity. The steady-state conditions assumed during traditional manufacturing processes are not valid in AM, because of the spatial and temporal transients imposed by the abrupt, cyclical changes in energy delivery. As a result, the intrinsic microstructural heterogeneity throws new challenges at the familiar notion of a ‘microstructure-property’ relationship. This lecture will present recent advances in the way that the electron microscope and the atom probe microscope have enabled insights into this complex relationship. Recent breakthrough methodological advances in Transmission Kikuchi Diffraction, 3D-electron backscattered diffraction, aberration corrected scanning transmission electron microscopy, and atom probe microscopy will be presented in the context of how these techniques are enabling the generation of critical quantitative data for AM process control.
3:35 PM Keynote
Texture and Anisotropy in Metals Additive Manufacturing: Anthony Rollett1; Joseph Pauza1; 1Carnegie Mellon University
Effectively all alloys currently used for printing are cubic, which means they freeze with <001> biased towards the temperature gradient direction. Moreover, epitaxial growth from the base metal dominates, which sets up a classic growth competition. Naively, one might then expect all prints to exhibit a strong <001> fiber texture parallel to the build direction (BD), given that heat extraction is generally unidirectional through the base plate. The typically strong elastic anisotropy would then result in the BD being more compliant than in the plane. Remembering, however, that prints comprise thousands of welds threading the volume in different directions, the weak textures generally obtained are a consequence of the wide range of local growth directions. Phase transformation, e.g., Ti, further disperses orientation. Exploiting 3D printing to control anisotropy via texture therefore requires subtle methods to control the local growth direction(s), which will be illustrated by experiment & simulation.
4:05 PM Break
4:25 PM Keynote
TMS Young Innovator in the Materials Science of Additive Manufacturing Award: Innovation in Additive Manufacturing: A Perspective on an Early Career in Metal Alloy Development: Douglas Hofmann1; 1NASA Jet Propulsion Laboratory/California Institute of Technology
The past decade has seen rapid and widespread adoption of additive manufacturing technology at NASA’s Jet Propulsion Laboratory/California Institute of Technology. This talk focuses on the establishment of AM capabilities at JPL and subsequent infusion opportunities in spacecraft, with particular emphasis on alloy development, prototyping, testing, and processing and property relationships. AM is an attractive capability for infusion into spacecraft, especially for complex part designs, multifunctional materials, extreme environment materials, hardware with reduced cost and schedule, and low mass structural parts. JPL now has a large team of scientists, engineers and technologists working in AM with a subset working in alloy development. Some of the AM research topics that will be covered in this talk include functionally graded metals, bulk metallic glasses, metal-matrix composites, self-hammering excavating tools, graded dielectric antennas, and multi-functional materials.