Effects of strain rate and internal hydrogen on tensile properties of Al-10%Mg alloys

Abstract

Strain rate dependences on tensile properties of the Al-10%Mg alloys containing high (5000H) and low (5000L) internal hydrogen were investigated. The total and uniform elongations increased with decreasing strain rate although the changes of tensile and yield strengths were small in 5000L. On the other hand, the total and uniform elongations also increased with decreasing strain rate whereas the tensile strength slightly increased and yield strength were almost constant in 5000H. The total and uniform elongations of 5000L at low strain rate were high in comparison with those of 5000H. A lot of cracks were observed at the particles consisting of Al-Mg-Mn in both 5000H and 5000L after tensile test. A lot of acoustic emission events (counts) were detected during plastic deformation in 5000H in comparison with those in 5000L. The low total and uniform elongations of 5000H at low strain rate might be attributed to the promotions of void and crack initiation, growth and propagation owing to the acceleration of cracking of particles due to the internal hydrogen which is introduced during casting process.