Comparison of ductile fracture properties of aluminum castings : Sand mold vs. metal mold

摘要: Abstract This paper compares mechanical properties of two types cast aluminum components made in sand molds and iron molds, respectively. For each type the castings, a total 12 fracture tests are performed under wide range stress states including 6 tensile on notched unnotched round bars biaxial loading butterfly specimens. Using combined experimental–numerical approach, plasticity characterized terms true stress–strain curve ductile locus. It is found that sand-molding component higher yield resistance lower ductility than metal-molding one. Meanwhile, fractographic study reveals there exist competing failure mechanisms: internal necking matrix at high positive triaxialities void sheeting due to shear negative triaxialities. The transition modes occurs intermediate range. suggests locus formulated space triaxiality effective strain consist three branches rather monotonic curve.