2009 Volume 50 Issue 12 Pages 2790-2794
In order to elucidate the mechanism of the high temperature embrittlement of Al-5 mass% Mg alloys containing traces of sodium, microscopic observation of grain boundaries during quasi-static and impact tensile deformation was carried out. The high temperature embrittlement during the quasi-static deformation was caused by a combination of grain boundary sliding and grain boundary serration. On the other hand, the high temperature embrittlement during the impact deformation was caused by the localization of stress concentration at the grain boundaries. This localization was due to planar slips.