Design of tailored materials: from principle component alloys to metamaterials
Abstract
The development of new materials that have significantly higher strain hardening and strain-rate hardening characteristics incombination with increased yield strength and ductility (toughness) promise substantial improvement to the impulsive load resistance of future structures. The proposed work comprises of two interconnected activities: TASK 1: The effort will focus on the development of static and dynamic multiaxial micromechanical models for fcc MPEs such as Fe20Cr20Mn20Ni20Co20 and the validation of these models with testing of alloys provided by the University of Virginia as part of the ONR Basic Research Challenge (BRC) effort. Additional characterization work would establish the evolution of dislocation density and the twin density with strain and multiaxial stress state. This data would then be used to adapt existing models for TWIP/TRIP-based material systems to account for texture and other effects in systems of very low stacking fault energy (and therefore highly dissociated dislocation core structures). The constitutive models would be extended to address the strain rate dependence of each of the underlying mechanisms of deformation and used to identify improved MPE alloys with the more promising combinations of specific strength, strain hardening rate and ductility/toughness, and investigate potentially significant improvements in ballistic, blast and impact resistance. TASK 2: This research effort will develop Bayesian and Deep-learning based optimisation tools for predicting the optimal combinations of topology, internal material length scales, levels of structural hierarchy andmaterial combinations to achieve tailored properties that include: (i) strength and toughness that lies in the white space of the Ashby material maps and (ii) specified stress versus strain curves to optimise the impact protection capability of materials. The designs will beconstrained based on available processing routes and manufactured and tested at Virginia Tech to confirm the fidelity of the designs and optimisation procedures. This effort will develop computational tools for the design of arbitrary, complex 3-D shapes with topological feature sizes spanning orders of magnitude in length scales from tens of nanometers, to micrometers, centimeter and above using additive manufacturing processes.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 19, 2018
- Source ID
- N000141812658
Entities
People
- Vikram S Deshpande
Organizations
- Office of Naval Research
- United States Navy
- University of Cambridge