Design of nanocrystalline alloys with superior wear resistance: Multiscale simulations and experiments
Abstract
Synthesis of materials that exhibit ultra-low wear rates is important for both efficient metal manufacturing processes (e.g., cutting, cold-working) and engineering of durable components in applications that involve sliding contacts (e.g., piston-cylinder contacts, engine injection sections, orthopedics, electrical contacts, and general bearings). A critical factor in the rational design of materials that experience high contact loads is the understanding of how the microstructure evolves in situ at the sliding contact. Such an understanding has been challenging to achieve due to limitations in experimental techniques for in situ monitoring of nano/microstructural evolution at buried interfaces. For this reason, developments of metal alloys for tribological applications have been to a large extent based on empirical rules, rather than on a scientific understanding of the underlying physical phenomena. Here, the above challenge will be addressed by (i) developing a new framework for experimentally validated mesoscale models capable of simulating microstructural evolution in sliding contacts and (ii) combining scanning TEM contrast imagining of the tested material with massively parallel molecular dynamics (MD) simulations, in order to identify fundamental design principles for optimizing tribological performance of metal alloys. This study will focus on nanocrystalline metal alloys because these materials are expected to exhibit superior mechanical properties as compared to their coarse-grained counterparts. Experiments and modeling will be performed on Al and Cu alloys because of their technological importance, although the developed principles and models can be generalized to other nanostructured metallic systems. The grain size and chemical composition of the alloys prior to mechanical testing will be varied by changing synthesis conditions. The proposed research will lead to: (i) fundamental discoveries of how microstructure of metal alloys evolves in sliding contacts; (ii) understanding of how a nanocrystalline tribolayer affects friction and wear resistance of alloys; (iii) development of an experimentally validated modeling framework for simulating frictional response of metal alloys. The fundamental understanding and models developed over the course of this project will provide a foundation for rational design of multi-component alloys with complex nano/ microstructures for tribological applications. During the three years of the project, research efforts will be focused on: Year 1 Ð synthesis of alloys, macroscale measurements of friction and wear, developments of new capabilities in the mesoscale model. Year 2 Ð single-asperity measurements of friction, characterization of deformed microstructures, validation of the mesoscale model, MD simulations of friction and wear; Year 3 MD simulations to discover how dislocations interact with interfaces, mesoscale simulations to discover the role of different deformation mechanisms and materials processes as well as of the effects of their coupling on friction and wear.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 06, 2018
- Source ID
- W911NF1710571
Entities
People
- Izabela Szlufarska
Organizations
- Army Contracting Command
- United States Army
- University of Wisconsin–Madison