Short Time Compressive Creep in 75S-T6 and 25S-T6 Aluminum Alloy Short Columns

Citation

Thatcher, Roland Churchill (1952) Short Time Compressive Creep in 75S-T6 and 25S-T6 Aluminum Alloy Short Columns. Engineer's thesis, California Institute of Technology. doi:10.7907/DFBM-7A50. https://resolver.caltech.edu/CaltechETD:etd-03302009-083614

Abstract

The creep characteristics of some of the light metal alloys at high temperature and stress were investigated when subject to; (1) Tension, (2) Short Column Compression, (3) Long Column effect. The tension and long column aspects are covered in the theses of R. I. Kauffman and R. Gaibler respectively. This thesis concerns the short-time creep of short columns of 25S-T6 and 75S-T6 aluminum alloy, subjected to large compressive loads, and temperatures of 450°, 500°, and 550°F. The columns were circular in cross section, and had an effective slenderness ratio of 25.5.

It was found that 75S-T6 was superior to 25S-T6 at 450°F and, that at that temperature, 75S-T6 short columns could withstand a stress of 14,500 psi, however due to creep, failure occurred in approximately 45 seconds. At a temperature of 500°F, 25S-T6 was found to be superior, and withstood a stress of 11,000 psi for approximately 60 seconds before creep failure occurred. The load carrying ability of the two alloys was about the same at 550°F with both materials withstanding 8,000 psi for approximately 60 seconds.

It is commonly believed that aluminum alloys are of little value at temperatures as high as 550°F, however contrary to this belief, this investigation shows that short columns of the two alloys tested can carry a large compression load if the time of duration is short.

Thesis Files