Insights into particle dispersion and damage mechanisms in functionally graded metal matrix composites with random microstructure-based finite element model

This study investigates the impact of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msub><mml:mi>Al</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:msub><mml:mi>O</mml:mi> <mml:mn>3</mml:mn></mml:msub> </mml:mrow> </mml:math> particle volume fraction and distribution on the deformation and damage of particle-reinforced metal matrix composites, particularly in the context of functionally graded metal matrix composites. In this study, a two-dimensional nonlinear random microstructure-based finite element modeling approach implemented in ABAQUS/Explicit with a Python-generated script to analyze the deformation and damage mechanisms in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>AA</mml:mi> <mml:mn>6061</mml:mn> <mml:mtext>-</mml:mtext> <mml:mi>T</mml:mi> <mml:mn>6</mml:mn> <mml:mo>/</mml:mo> <mml:msub><mml:mi>Al</mml:mi> <mml:mn>2</mml:mn></mml:msub> <mml:msub><mml:mi>O</mml:mi> <mml:mn>3</mml:mn></mml:msub> </mml:mrow> </mml:math> composites. The plastic deformation and ductile cracking of the matrix are captured using the Gurson-Tvergaard-Needleman model, whereas particle fracture is modelled using the Johnson-Holmquist II model. Matrix-particle interface decohesion is simulated using the surface-based cohesive zone method. The findings reveal that functionally graded metal matrix composites exhibit higher hardness values ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mtext>HRB</mml:mtext></mml:math> ) than traditional metal matrix composites. The results highlight the importance of functionally graded metal matrix composites. Functionally graded metal matrix composites with a Gaussian distribution and a particle volume fraction of 10% achieve <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mtext>HRB</mml:mtext></mml:math> values comparable to particle-reinforced metal matrix composites with a particle volume fraction of 20%, with only a 2% difference in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mtext>HRB</mml:mtext></mml:math> . Thus, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mtext>HRB</mml:mtext></mml:math> can be improved significantly by employing a low particle volume fraction and incorporating a Gaussian distribution across the material thickness. Furthermore, functionally graded metal matrix composites with a Gaussian distribution exhibit higher <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mtext>HRB</mml:mtext></mml:math> values and better agreement with experimental distribution functions when compared to those with a power-law distribution.