Papers by Author: K.H. Kim

Abstract: An attempt has been made to clad Mg alloy with Al by twin-roll casting. This was done by inserting an Al sheet between the roll and the Mg alloy melt during twin-roll casting. Microstructural investigation across the transverse section of the as-cast Al-clad Mg alloy sheet reveals a very good interfacial bonding between Al and the base Mg alloy. Annealing of the Al-clad Mg alloy sheet results in the formation of layers of various intermetallic phases along the Mg/Al interface. Subsequent rolling of the as-annealed sheet significantly improves the formability of the reaction zone, as evidenced by the cracking of the base Mg alloy before the cracking of the reaction zone.

Abstract: Room temperature formability of twin-roll cast Mg alloys has been investigated and correlated with their work hardening behavior. Tensile properties of these alloys were measured and their work hardening behaviour was analysed by using constitutive equations. Room temperature formability of the alloys was evaluated by the limiting dome height (LDH) value, obtained by the Erichsen cupping test. It shows that there is a linear relationship between LDH value and the inverse of yield ratio, which is a function of work hardening exponents. An increase in grain size increases work hardening exponent and concurrently increases LDH.