FENOMENA DYNAMIC STRAIN AGING PADA PROSES TEMPA PANAS PADUAN Co-33Ni-20Cr-10Mo[Dynamic Strain Aging Phenomena of Co-33Ni-20Cr-10Mo Alloy During Hot Forging]

Abstract

DYNAMIC STRAIN AGING PHENOMENA OF Co-33Ni-20Cr-10Mo ALLOY DURING HOT FORGING. In the present study, hot deformation characteristic in Co-33Ni-20Cr-10Mo superalloy was carried out by using hot compression test in the temperature range from 700-900 ºC and strain rates ranging from 0.01-30 s–1 with a constant strain 0.5. The flow curves showed high work hardening rate at those temperatures. At temperatures 700-750 ºC, the 0.2 % flow stress decreased with increasing strain rate, while at temperatures 800-850 ºC, the 0.2 % flow stress is independent of a strain rate. Negative strain rate sensitivity was obtained at temperatures 700-900 ºC, suggesting the dislocation solute interaction occurred in those temperature ranges. DSA come from Suzuki segregation; chemical interaction between solute atoms and stacking faults bonded by the shockley partials. DSA is categorized as one of catastrophic phenomena in a hot working process of Co-33Ni-20Cr-10Mo superalloy.