RESEARCH ON PROPERTIES OF HIGH STRENGTH MATERIALS SUITABLE FOR HIGH TEMPERATURE APPLICATIONS

Investigations of the fatigue behavior of high-strength alloys were continued. Bars of iron- molybdenum alloys, intended for study as to suitability for ball bearings at temperatures up to 1000 deg F were found to be so non- homogeneous and brittle that specimens could not be machined from them. High- temperature torsion tests of relaxation were made to study the suitability of two alloys, M-1 tool steel and Inconel X, for springs at 1000 deg F, and of two alloys, Waspalloy and Udimet 500, for springs at 1500 deg F. Alternating torsion of plus or minus 10 ksi, superimposed on an initial steady stress of 25 ksi, was applied to specimens of each alloy. Inconel X lost about 10 to 15% of the steady load in about 100 hr. The other three alloys relaxed two or three times as much. (auth)