Thermal-Stress Fatigue Behavior of Twenty-Six Superalloys

Abstract

The comparative thermal-stress fatigue resistances of 26 nickel- and cobalt-base alloys were determined by fluidized bed tests. Cycles to cracking differed by almost three orders of magnitude for these materials, with directional solidification and surface protection showing definite benefit. The alloy-coating combination with the highest thermal-stress fatigue resistance was directionally solidified NASA TAZ-8A with an RT-XP coating. Its oxidation resistance was also excellent, showing approximately a ½ percent weight loss after 14 000 fluidized bed cycles.

Thermal‐mechanical Fatigue of Mar‐m 509 Superalloy. Comparison With Low‐cycle Fatigue Behaviour

“…Att = Acp i-Ace (4) where Atp, Ace and Ac, are the plastic, elastic and total strain ranges, Aa is the stress range, t; and o; are the fatigue ductility and fatigue resistance coefficients and c and b ductility and resistance coefficients.…”

Thermal Fatigue of Mar‐m509 Superalloy—i. The Influence of Specimen Geometry

“…Glenny in the late fifties introduced a fluidized bed technique using tapered disc specimens [l, 21. This technique was also widely used later by other authors using wedge type specimens [3,4]. For a long time this test was mainly used to compare the thermal fatigue resistance of candidate materials for turbine components.…”