| Title |
Uniaxial Tear Characteristics for A1-7%Si-0.4%Mg Cast Alloys with Directional Dendritic and Globular Cell Structures |
| Authors |
한상원(Han Sang Won); 김석원(Kim Seog Won) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Al-Si-Mg cast alloys; Pop-in stress; Slant fracture surface; Fracture toughness |
| Abstract |
Tear resistance behaviors of Al-7%Si-0.4%Mg cast alloys were examined using Kahn-type tear test specimens which are distinguished DCC(directional continuous cast) consisting of a directional and ordinary dendrite structure with SLD(semi-liquid die cast) consisting of globular cells and fine grain structure. Restricted plastic deformation occurs near notch tip of semi-liquid die cast characterized by refinement of grain size. Popin for stress was exhibited in semi-liquid die cast but no pop-in was observed in DCC cast alloy. Tear resistance was evaluated by the energies required for crack initiation, UE_(i) and the crack propagation, UE_(p). An unit propagation energy, UE_(p) can be converted into critical stress intensity factor, K_(c), which in directional dendrite structure improves due to a high plane stress state over thickness-direction and the fracture surface of slant type. |