An investigation of the as-quenched and early aging characteristics of a Al - 4.1wt%Li binary alloy by X-ray diffraction

Abstract

The as-quenched and early aging characteristics of an as -cast binary, Al - 4.1 wt. % Li alloy has been studied by X-ray diffraction. Flat plate samples were solution heat treated at 540 C under argon and ice-brine quenched. Powder samples were made from flat plate samples in the as-quenched condition by filing at liquid nitrogen temperatures. Aging was conducted at 200 C on both plate and powder samples. The presence of very broadened 100 superlattice reflections of delta'Al3Li (Ll2 structure) and small reflections of delta Alli(B32 structure) were observed in the as-quenched condition for the plate sample. The powder sample showed the additional 110 superlattice peak of delta and 220delta peak. This clearly showed the preferred orientation effects of the plate. From as-quenched powder, a volume fraction of 77% with an average particle diameter of 53 angstroms was calculated.