Investigation of Reversion Stresses Generated in Fe-Ni-Co-Ti Alloy

摘要

The reversion stress values were measured using the following test procedure:(1)austenitic samples were deformed by a constant load (400 MPa) at T> A_f. (2) tense samples were cooled down to 77 K maintaining the same level of stresses (400 MPa) to obtain strain 3percent. (3) the samples were heated to T> A_f for different values of the load generating stresses (#sigma#_R) and temperature dependences of recovered strain #epsilon#_R=0 were recorded. As a result, the plot #sigma#_R vs #epsilon#_R was obtained. Extrapolating this curve to #epsilon#_R=0 (the fully constraint condition), the maximum reversion stress was evaluated to be equal to #sigma#_R~m≈1000 MPa. The thermal cycling through the interval of #gamma# reversible #alpha# transformation of the loaded sample causes the increase of reversion stress.