An Analysis of Strengthening Mechanisms and Rate-Dependence in a High Strength Aluminum Alloy

  • B. Cao
  • M. Shaeffer
  • D. Cadel
  • K. T. Ramesh
  • S. Prasad


We examine the strengthening mechanisms within a high-strength aluminum alloy with the objective of providing guidelines for increased strength. First, we measure the mechanical behavior of the age-hardenable Al–Cu–Mg–Ag alloy known as Al 2139 in the T8 condition, and observe strengths of 500 MPa at quasistatic strain rates and average strengths of up to 600 MPa at high strain rates. Next, we explore the reasons for the high strength of this alloy by considering the contributions of various strengthening mechanisms to the total strength of the material. Finally, we develop an analytical approach to estimating the strengthening developed through the mechanism of dislocation cutting of closely spaced plate-like semi-coherent precipitates. Our results suggest that dislocation cutting of the \(\Omega\) phase is the primary strengthening mechanism in this alloy.


Mechanisms Strength High strain rate Aluminum 



The authors acknowledge support from the Army Research Laboratory under ARMAC-RTP Cooperative Agreement number W911NF-06-2-0006. KTR acknowledges support from the Army Research Laboratory through Cooperative Agreement Number W911NF-12-2-0022. We gratefully acknowledge the technical assistance of D. Nguyen with Kolsky bar tests, and of Dr. Kenneth Livi with the STEM.


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© Society for Experimental Mechanics, Inc 2017

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringThe Johns Hopkins UniversityBaltimoreUSA
  2. 2.CSIR-National Metallurgical LaboratoryJamshedpurIndia

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