Small-punch tests were conducted at 4, 77, and 293 K on three newly developed cryogenic austenitic stainless steels, JN1, JJ1, and JK2, which were solution treated, water-quenched, and then aged at 923, 973, 1023, and 1073 K for 5 h. Small-punch test energy was employed for the evaluation of the aging-induced embrittlement behavior in these materials. An SEM analysis of the fracture surface for the solution-treated steel specimens indicated a ductile fracture, having the highest SP test energy values. On the contrary, intergranular brittle fracture was observed in aged specimens. The small-punch test energy of materials decreased significantly as the aging process progressed. The highest and lowest decrease in small-punch test energy with aging temperature occurred in JN1 and JK2 steels, respectively. The decrease in small-punch test energy was shown to follow appropriately the aging-induced embrittlement in these materials. The difference in aging-induced embrittlement behavior for these steels was explained on the basis of the volume fraction of intergranular precipitates in aged samples.
Material characterization procedure of degradation of austenitic stainless steels by use of Small Punch test and electrochemical potentiokinetic reactivation (EPR) method.
