1. Effect of Interface Strength on the Mechanical Properties of PRMMCs Xee Thao1, J.B. Ferguson1, Pradeep K. Rohatgi1, Kyu Cho2, and Chang-Soo Kim1 1Materials Science and Engineering Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA 2U.S. Army Research Laboratory, Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD 21005, USA

2. Introduction What is a composite? Why chose composites? http://www.engineeringcivil.com/wp-content/uploads/2013/04/Fig-1-Matrix-and-Reinforcement-in-a-composite-material.jpg http://www.highsnobiety.com/files/2013/02/The-Ultra-Lightweight-Blackbraid-Bike-6.jpg

3. Objective • Use computational finite-element analysis (FEA) to develop a unit cell approach for a representative volume element (RVE) • Study the mechanical responses of varying reinforcement size and volume fraction in Al2024/SiCparticle reinforced metal matrix composites (PRMMCs). • Examine how the interface strength affects the overall mechanical properties of (PRMMCs)

4. Approach • ABAQUS was used to perform numerical simulations. • The model consisted of a simple cubic array. • A load was applied and displacement was measured to generate the composite stress vs strain curves. http://lori.ru/722596

5. Conditions • Periodic boundary conditions (PBC). • Tie constraints between particle and matrix surfaces. • Tensile test: Load of 500 MPato the top and bottom planes of the model.

6. Method • Varied total volume fraction of reinforcement from ~3%-12.5%. • NxNxN reinforcement particle arrangement. N varied from 1 to 5. • Modified Poisson’s ratio of reinforcement. • Altered bond strength, by altering surface area tied. Remaining surfaces were in hard contact.

7. Results Variations of calculated elastic modulus and 0.2% offset yield stress with: • number of particles • particle volume fraction

8. Results Variations of calculated elastic modulus and 0.2% offset yield stress with: • 100%, 75%, 50%, 0% bonding • particle volume fraction

9. Computation vs experiment • strongly bonded Al-2080/SiC (solid symbols and lines) • poorly bonded Al-2024/Al2O3 (open symbols and dotted lines)

10. conclusion • A 3D computational tool has been developed to accurately predict the elastic modulus and yield strength for PRMMCs. • For fixed volume fractions of reinforcement, increased N values showed no major increases in yield stress and Young’s modulus. • The Poisson’s ratio was investigated and determined to be a second order effect for both elastic modulus and yield stress. • Ongoing efforts in numerical development to further realize the properties attributing to strengthening mechanisms found in PRMMCs