Nanoindentation characterization on the temperature-dependent fracture mechanism of Chinese 316H austenitic stainless steel under creep-fatigue interaction

Nanoindentation characterization on competing propagation between the transgranular and intergranular cracking of 316H steel under creep‐fatigue loading

“…The value of m is extended to reveal the mechanism of indentation creep 42,43 . The simplified method to estimate the value of m is used in this work, as follows 26,44 : where t 1 and t 2 are the time at the beginning and end of the holding period at the secondary creep stage, respectively. From Equation (1), the average value of m with a certain time interval [ t 1 , t 2 ] could be estimated.…”

“…The value of m is extended to reveal the mechanism of indentation creep. 42,43 The simplified method to estimate the value of m is used in this work, as follows 26,44 :…”

“…However, the CF behaviors and microstructures of the austenite stainless steel (316H) and martensitic steel are totally different. Under CF loading, the cyclic softening behavior and enhanced block grains were observed in martensitic steel, 23–28 while the occurrence of an initial hardening period and small recrystallized grains was reported in the austenite stainless steel 29,30 . Based on these experimental results of the austenitic stainless steel AISI 316, Hales 31 proposed four kinds of damage mechanisms: transgranular cracking (fatigue driven only), intergranular cracking (creep driven only), transgranular cracking interlink with creep voids (CF interaction), and transgranular competing propagation where both fatigue and creep (obey their own failure criteria without interaction).…”

“…On the other hand, the CF interaction of alloys is also studied by performing the dwell-fatigue experiments. 21,22 In our previous studies, [23][24][25][26][27][28] the microstructural evolution of martensitic steel and/or welded joint during dwell-fatigue tests was investigated. However, the CF behaviors and microstructures of the austenite stainless steel (316H) and martensitic steel are totally different.…”

Optimization of Lapping and Polishing of Steel Samples for Nanoindentation Based on SVM-GA

“…With the fast development in the fabrication of structures on the functional materials used in aerospace engineering, renewable energy engineering, and microelectronics engineering, the characterization of material properties at the microscale and nanoscale levels must be accurately obtained (Reggente et al, 2020;Hossain et al, 2022). Currently, nanoindentation is considered a powerful technique used to quantitatively characterize the mechanical properties of different kinds of materials (Das et al, 2022), and by fitting the appropriate models to the curve of force with respect to displacement obtained from the test, the major material properties, such as the elastic modulus, hardness, and fracture toughness can be measured at the microscale and nanoscale (Isik et al, 2022;Song et al, 2022). Since the indentation depths are in the order of nanometers, the surface quality of the sample has an essential effect on the nanoindentation test (Chen et al, 2014).…”