Optimizing the Dynamic Response of Ultrafine Grain and Hybrid Alloys under Impact Loading
Abstract
Objectives and Methods: Aluminum alloys are attractive materials for structural applications in ground vehicle and aerospace structures due to their low density and high specific strength. Many high strength aluminum alloys however offer low resistance to impact and shock loads because of their tendency to suffer heterogeneous deformation leading to intense strain localization along narrow paths called the adiabatic shear bands (ASB). These bands act as precursors to fracture of structures under dynamic impact loading. The overall goal of this proposal is to determine the effect of grain size, temper condition, initial texture and composition on the dynamic impact response of ultrafine grain aluminum (UFG) and hybrid alloys under impact loads. The key thrusts of this research are to: i) produce UFG alloys and determine the effects of strengthening by grain refinement on their resistance to ASB formation and impact failure, ii) evaluate the role of initial texture and temper condition on plastic deformation mechanism, damage evolution and occurrence of ASB in the UFG alloys, ii) produce and characterize new multilayered hybrid alloys for optimum combination of mechanical properties under and resistance to ASB formation, propagation and impact failure, iv) determine the effects of minor alloying elements and the role of second phase particles and precipitates on texture evolution, strain localization and micromechanism of ASB formation in the selected alloys, and v) develop physics-based models suitable for studying adiabatic shear instability in the aluminum alloys under dynamic loading.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 12, 2016
- Source ID
- W911NF1510457
Entities
People
- Gdadebo Owolabi
Organizations
- Army Contracting Command
- Howard University
- Office of the Secretary of Defense