Micromechanical analysis of residual stress and tensile behavior of
aluminum composites reinforced with irregularly arranged fibers
Abstract
Aluminum matrix composites reinforced with irregularly arranged fibers
was fabricated using liquid metal infiltration technology. The
cooling-induced residual stress and the subsequent tensile behavior were
investigated by numerical and experimental method. The results show that
the macroscopic thermal shrinkage curves obtained from the numerical
simulation are consistent with the experimental ones. After the cooling
process, the matrix and fiber are in the tensile and compressive stress
states, respectively. The irregular fiber arrangement leads to an
inhomogeneous residual stress distribution, which causes the plastic
deformation and damage initiation of the matrix alloy within the
smallest inter-fiber gaps. The numerical simulations involving the
residual stress yield the tensile stress-strain curves that are in good
agreement with the experimental ones. The cooling-induced residual
stress and local damage promote the failure evolution behavior of the
matrix and interface during the tensile process. As a result, the
presence of residual stress resulted in reductions in axial strength and
elastic modulus of 17.1% and 18.2%, and in transverse strength and
fracture strain of 11.4% and 10.6%. The failure modes obtained from
the numerical simulations are further validated by the fracture
morphology of the tensile specimens.