TY - JOUR
T1 - Influence of temperature-dependent viscoplastic relaxation and strain-induced martensitic transformation on the fatigue life of 304L stainless steel
AU - Mansour, R.
AU - Enblom, P.
AU - Subasic, M.
AU - Ireland, A.
AU - Gustavsson, F.
AU - Forssgren, B.
AU - Efsing, P.
N1 - Publisher Copyright:
© 2025 The Authors
PY - 2025/9
Y1 - 2025/9
N2 - This work investigates the interaction between two competing mechanisms on the fatigue life of 304L stainless steel, martensitic transformation and viscoplastic relaxation, as well as the potential fatigue life enhancement of a single hold time applied prior to cyclic loading. At 300 °C, a tensile load hold time of 15 h applied prior to alternating cyclic loading resulted in an increase in mean fatigue life, exceeding 20 % in the studied low cycle fatigue regime. The observed enhancement is primarily attributed to viscoplastic effects during the hold time, which reduces the maximum stress and fatigue crack growth rate in cyclic loading. At room temperature, the opposite effect was observed. A strain-induced martensitic transformation resulted in a secondary cyclic hardening and a brittle final softening phase. The transformation was enhanced by the hold time, which led to increased brittleness and therefore reduced fatigue life. However, viscoplastic relaxation attenuated the detrimental effect of martensite, as was observed by a 15 % decrease in maximum stress. This study not only demonstrates the positive impact of an extended hold time at elevated temperature on the low cycle fatigue behavior but also analyzes underlying competing mechanisms at room temperature through an in-depth experimental investigation.
AB - This work investigates the interaction between two competing mechanisms on the fatigue life of 304L stainless steel, martensitic transformation and viscoplastic relaxation, as well as the potential fatigue life enhancement of a single hold time applied prior to cyclic loading. At 300 °C, a tensile load hold time of 15 h applied prior to alternating cyclic loading resulted in an increase in mean fatigue life, exceeding 20 % in the studied low cycle fatigue regime. The observed enhancement is primarily attributed to viscoplastic effects during the hold time, which reduces the maximum stress and fatigue crack growth rate in cyclic loading. At room temperature, the opposite effect was observed. A strain-induced martensitic transformation resulted in a secondary cyclic hardening and a brittle final softening phase. The transformation was enhanced by the hold time, which led to increased brittleness and therefore reduced fatigue life. However, viscoplastic relaxation attenuated the detrimental effect of martensite, as was observed by a 15 % decrease in maximum stress. This study not only demonstrates the positive impact of an extended hold time at elevated temperature on the low cycle fatigue behavior but also analyzes underlying competing mechanisms at room temperature through an in-depth experimental investigation.
KW - Cyclic hardening and softening
KW - Fatigue life
KW - Stainless steel
KW - Strain-induced martensitic transformation
KW - Viscoplastic relaxation
UR - http://www.scopus.com/inward/record.url?scp=105002489780&partnerID=8YFLogxK
U2 - 10.1016/j.ijfatigue.2025.108992
DO - 10.1016/j.ijfatigue.2025.108992
M3 - Journal article
AN - SCOPUS:105002489780
SN - 0142-1123
VL - 198
JO - International Journal of Fatigue
JF - International Journal of Fatigue
M1 - 108992
ER -