Effect of Thermal Cycling and Hydrogen Absorption on Selected Properties of 55-Nitinol

摘要

The unique ability of the alloy 55-Nitinol to be restored to a predetermined shape by moderate heating, and to exert considerable force during the shape-restoration, makes it attractive for certain mechanical systems. An important requisite to its utilization was a knowledge of how the alloy would be affected by a H environment and by thermal cycling in this temperature range encountered under ambient conditions. After 500 thermal cycles from -100 to +165 exp 0 F, 55-Nitinol displayed the same ability to be restored to its memory shape as it had before cycling. Similarly, the force exerted when the alloy was completely restrained while it was heated beyond its shape-recovery temperature was not changed by thermal cycling. When the upper limit of the thermal cycling was 200 exp 0 F, which is above the temperature at which shape recovery can occur, both the shape change characteristics and the force characteristics were changed. H introduced to a level of 100 ppM, did not change the shape-recovery behavior or force behavior. (ERA citation 05:005967)