An investigation was made of the creep characteristics of two aluminum alloys, 75S-T6 and 25S-T6, and one magnesium alloy, FS-1, under the conditions of high temperatures and high stresses. These alloys were selected as being representative of the light alloys in current use in the aircraft industry.
This investigation was divided into three phases: (1) "fast-rate" deformation under tension, (2) creep of short columns in compression, and (3) lateral deflection creep of columns. This thesis encompasses only the first phase of the investigation. The other phases are covered by current theses by the author's coworkers.
It was found that the aluminum alloys tested were superior in creep resistance to the magnesium alloy at the common temperatures used, 450°F and 500°F. However, the comparative creep resistance of the aluminum alloys was dependent upon the temperatures at which the alloys were compared: 75S-T6 being superior at 450°F, 25S-T6 at 500°F, and neither alloy superior to the other at 550°F.
The possible use of the alloys tested for short duration under conditions of high temperatures and high stresses is noted.
The data obtained is presented in both tabular and graphic form with various cross-plots provided for the purposes of cross comparison and to permit easy reference for obtaining given creep characteristics of the alloys tested.
