Mg-Nd-Zn-Zr 합금의 크리이프 특성에 관한 연구

Abstract

Recently, as the modern industry development it is increasing that the necessity of magnesium alloy creep deformation and characteristics. This paper has been studied about the creep strength of Mg-Nd-Zn-Zr alloy. For the alloy, pure magnesium ingot of 99.9% was melt with atmosphere of 0.3% SF6 and 25% CO2. After melting, zinc of 0.3% was inserted to stir during 10min and elevated up to 770℃. Master alloys of Mg-15% Nd and Mg-15% Zr were stirred in furnace. To predict deformation mechanisms, the apparent activation energy Qc and the applied stress exponent n, rupture life have been determined during creep behavior of the magnesium alloy at the temperature range of 200∼220℃, 280∼300℃ and stress range of 200∼220kg, 100∼120kg. The deformation mechanism was predicted dislocation climb from measured apparent activation energy and stress exponent. Also the increaser the temperature and stress the lower the stress exponent and activation energy, respectively. Also, the organizing photo of magnesium alloy was compared before and after creep with SEM(scanning electron micro scope). And the increasing the temperature and stress are more apparent shape of the fracture face.