Manufacturing Process Science: The Science of Processing/Alloying Windows in Metals Additive Manufacturing
Abstract
Metal-based Additive Manufacturing (AM) has recently received much attention as it potentially enables the manufacturing of parts with high degrees of geometric complexity, in addition to its attractive capability of tailoring microstructure, and in turn properties, within the same fabricated part through controlling manufacturing processing conditions. In defense applications, AMÕs disruptive nature can significantly reduce total ownership cost of defense systems, enhance operational availability of components near their points-of-use, and improve warfighter readiness. Indeed, AM is seen as one of the key strategic components of the ArmyÕs Agile Expeditionary Materials Manufacturing initiative, as it can potentially enable the responsive, on-demand manufacturing of mission critical products while retaining maneuverability by reducing the logistics tail. Despite notable technological advances in AM technologies over the past decade, significant gaps are yet to be bridged in order to bring them to their full maturity and unlock the opportunities described above. Perhaps one of the most critical roadblocks is the cost and time associated with the qualification and certification (Q&C) of AM materials and processes. Q&C is broadly defined as the process of ensuring that the properties of manufactured parts meet specifications in a repeatable and reproducible fashion. With the current absence of Q&C standards for AM, some mission critical parts can take up to 10-15 years and cost up to $300 million to certify using current methods that rely on extensive experimentation. On the other hand, while model-based Q&C using computational materials models and integrated computational materials engineering (ICME) platforms exists, there are still considerable technical barriers towards fully integrated, multi-scale, high-fidelity model-based Q&C. These barriers include the lack of current AM-targeted ICME models and the high computational burdens associated with these models. The complexity and cost of both experimental- and model-based Q&C efforts are exacerbated by the fact that metal AM has focused only on a handful of major material systems including titanium alloys, nickel alloys, and stainless steels, many which were not even initially designed to be manufactured using AM technologies. This is in contrast to other liquid-mediated materials processing technologies (such as welding and casting) where materials development and process planning and optimization have typically been conducted concurrently. The goal of the current project is to initiate and develop a research program focused on the basic science of metal AM, with special focus on establishing fundamental relationships between manufacturing process parameters, alloy phase stability, and the specific features of phase diagrams of the alloys to be fabricated with AM, and their impact on resulting micro/macro structures of AM parts. These relationships will be elucidated in a select number of simple, binary alloys, in particular Ni-based binary systems under a wide range of thermal histories achieved by spanning the AM parameter space. Thermal models coupled to experimental thermal monitoring will be used to build connections between process parameters (i.e. laser power, scanning speed, etc.) and thermo-physical conditions (cooling rates, thermal gradients), which in turn will be used to rationalize the connections between the thermal history of an alloy, its phase stability and the resulting microstructures. The project represents an important step forward towards the aspirational and long-term goal of developing a science-based framework for the design of materials and processes for AM.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1810278
Entities
People
- Raymundo Arróyave
Organizations
- Army Contracting Command
- Texas Engineering Experiment Station
- United States Army