EFFECTS OF SHOCK LOADING ON COBALT-BASED SOLID-SOLUTION STRENGTHENED SUPERALLOYS

Co-based HAYNES(R) 25(TM) and 188(TM) alloys have been studied to dete rmine the effect of shock-loading on the post-shock quasi-static and d ynamic mechanical response, and microstructural evolution. The compres sion properties of these materials were studied in both the as-receive d and shock-loaded conditions at strain rates from 10(-3)/s to 3000/s, and 77 and 293K. Isochronal annealing treatments were conducted at te mperatures ranging from 300 to 800 degrees C, following the shock-load ing. For annealing temperatures below 600 degrees C, the reload yield strengths and strain hardening rates were found to increase relative t o the as-shocked condition, and only at temperatures above 600 degrees C was the expected softening observed. The microstructural changes re sponsible for these differences in mechanical properties were document ed via TEM.