Enhanced Microstructures and Mechanical Performances of Additively Manufactured Metallic Alloys
Abstract
Motivation, Goals, and Methods: Additive manufacturing (AM) processes provide various advantages over conventional machining processes due to their short turnaround time and ability to create complex geometries. For some applications, AM-fabricated parts can be useful for prototyping multiple designs in a short time and for generating highly complex parts in a batch. However, AM-fabricated parts have some drawbacks due to their fabrication processes. For example, parts made by an AM process, such as selective laser melting, suffer from various defects such as pores, cracks, unmolten metal particles, and unfavorable microconstituents that are harmful to their mechanical performances. Additionally, many high strength metallic alloys offer low resistance to impact loads because of their tendency to suffer heterogeneous deformation leading to intense strain localization along narrow paths called the adiabatic shear bands. These bands act as precursors to fracture of structures under dynamic impact loading. The principal goals of this four-year proposed research are to: i) develop innovative approaches for eliminating defects and deleterious microconstituents that compromise the mechanical properties of metallic alloys produced via AM technology, ii) investigate process-microstructure-property relationships in nanostructured (NS) and ultrafine grained (UFG) AM-fabricated metallic alloys processed via severe plastic deformation, and iii) determine the effects of heat treatment and grain refinements on the porosity, deformation mechanisms, and mechanical performances of AM-fabricated metallic alloys. Key research trusts that will be used towards achieving the stated goals include: i) optimizing AM process parameters combined with appropriate thermomechanical treatments for defect elimination, ii) synthesizing and processing nanostructured and ultrafine grained materials, and iii) performing microstructural characterizations on the processed and deformed materials to observe the effect of each material processing conditions on their microstructures, deformation mechanisms, and mechanical performances. Expected Outcomes and Impacts: The proposed research will produce valuable information on how to use an innovative process optimization technique coupled with the application appropriate heat-treatment methods to eliminate defects and harmful microconstituent, thus enhancing the microstructures and mechanical performances of metallic alloys produced via AM technology. In addition, process-microstructure-property relationships for SPD-processed NS/UFG AM alloys will be established based on the outcomes of this proposed research to provide guidance that could be useful to researchers and engineers to evaluate the dynamic behavior of AM processed NS/UFG microstructures under impact and shock loads. The use of these low alloys with enhanced resistance to failure under dynamic impact loads is very crucial to minimizing fatalities when combat vehicles encounter improvised explosive devices in operation or when aircraft structures are struck by foreign objects. The research findings to be obtained from this study will be useful for future development of nanostructured and ultrafine grained alloys fabricated via AM technology. This integrated research and education will also enable Howard University (HU) to produce graduates that are equipped with strong knowledge and skills to address critical issues in the area of synthesis and processing of AM metallic alloys and their performances under, thereby enhancing HUÕs capability to recruit, retain, educate, and train young and promising students from underrepresented minorities.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 28, 2023
- Source ID
- W911NF2310218
Entities
People
- Gbadebo Owolabi
Organizations
- Army Contracting Command
- Howard University
- Office of the Secretary of Defense