EFFECT OF SERVICE STRESSES ON IMPACT RESISTANCE, X-RAY DIFFRACTION PATTERNS, AND MICROSTRUCTURE OF 25S ALUMINUM ALLOY

摘要

A great number of tests were made to determine the effect of service stresses on the impact resistance, the X-ray diffraction patterns, and the microstructure of 25S aluminum alloy. Many of the specimens were taken from actual propeller blades and others were cut from 13/16-inch rod furnished by the Aluminum Company of America. The average impact resistances were found to be unchanged even after 288,000 cycles in a 88,400 pound-per-square inch range that exceeded the fatigue limit and the original proof stress of the material.