Solidification and susceptibility to hydrogen absorption of AL–Si alloys containing strontium

Abstract

A study has been made of the effects of the addition of strontium, primarily at a level of 0·04 wt-%, on hydrogen absorption by molten Al–Si alloys of the LM 6 type, and on the solidification characteristics of the modified alloys as a function of cooling rate. Strontium enhanced the susceptibility of the alloys to hydrogen pick-up, the hydrogen concentration reaching a plateau during a 1 h hold period. With decreasing cooling rate, the strontium-modified alloys solidified with a scalloped eutectic interface growth front which is associated with a delay in forming a complete solid shell at the mould wall.MST/108