Publications
Experimental study of voids in high strength aluminum alloys
The ductile failure in metals has long been associated with void nucleation, growth and coalescence. Many micromechanics-based damage models were developed to study the effects of the voids sizes, shape and orientation to the nucleation, growth and coalescence of voids. However, the experimental methods to quantitatively validate these models were lacking. This paper is aimed to experimentally investigate at the microscale and nanoscale the effects of the shapes, sizes, orientation and density to the nucleation, growth and coalescence of voids and their relation to the ductility of the metal. In this work, notched tensile specimens with various radii were designed along different orientations. These specimens were tensile loaded up to different percentage of ultimate failure strain. The deformed specimens were then sectioned both along and perpendicular to the loading direction to microscopically study the voids size, shape and density. On the other hand, microtensile specimens were made out of these already deformed specimens. Using the advanced imaging capabilities of AFM and SEM combined with in-situ loading, the growth and coalescence of voids were in-situ studied at the microscale and nanoscale.