Pinning Effect of Cerium Inclusions during Austenite Grains Growth in SS400 Steel at 1300 °C: A Combined Phase Field and Experimental Study

Abstract

Abstract:The pinning effect of cerium inclusions in the austenite grain growth of SS400 steel at 1300 • C is investigated by using a semi-empirical-simulation. Firstly, steel samples containing cerium inclusions are prepared; then the properties of inclusions are determined using SEM. In situ observation of austenite grain growth is performed by LSCM, to determine the fitting parameters of the model such as the grain mobility and the pinning parameter. These parameters are directly inserted into our phase field simulation. The time-dependent Ginzburg-Landau (TDGL) equation is implemented in our phase field model, where the effects of inclusion and grain boundary interaction are inserted as a potential term in the local free energy. The results proved that the optimal size of austenite grains can be achieved by changing the volume fraction of inclusions. In fact, by increasing the volume fraction of inclusions from 0 to 0.1, the austenite grain growth can be decreased where the boundary mobility reduces from 2.3×10 −12 m 4 /Js to 1.0×10 −12 m 4 /Js. The results also demonstrated that increasing the temperature can provide more energy for grain to overcome the inclusions' pinning force. Moreover, it was shown that the classical Zener model, R c = 0.45r p f −1 i , describes the pinning effect of cerium inclusions.

A super‐hard high entropy boride containing Hf, Mo, Ti, V, and W

“…The presence of a secondary phase or grain boundary segregation led to lower grain sizes in HfMoTiVW_7.5 and HfMoTiVW_9 due to grain pinning. 18 A previous report of a nominally phase pure HEB containing Hf, Mo, Ti, and W had a significantly higher grain size, 13.4 ± 5.5 µm. VH values ranged from 27 GPa at a load of 9.8 N to as high as 66.8 ± 3.9 GPa at a load of 0.49 N, Figure 4.…”

“…The grain sizes increased from 2.7 ± 0.8 µm for MoTiVW_7.5, to 3.3 ± 0.9 µm for HfMoTiVW_9, and to 3.8 ± 1.2 µm for HfMoTiVW_10. The presence of a secondary phase or grain boundary segregation led to lower grain sizes in HfMoTiVW_7.5 and HfMoTiVW_9 due to grain pinning 18 . A previous report of a nominally phase pure HEB containing Hf, Mo, Ti, and W had a significantly higher grain size, 13.4 ± 5.5 µm 5 …”

Role of Cerium on the Intricacies of Deformed State and Softening Mechanisms of Low‐Carbon Steels

“…[2,3,5,17,18] In that context, the rare earth (RE) elements (mainly cerium [Ce]) added steels are one of the emerging counterparts that can demonstrate better performance at a low production cost. [2,7,[19][20][21][22][23][24] Ce-modified steels possess high strength and offer decent formability attributed to the modification of inclusions in the liquid steel and enhancement of strength through refined grain structure. [24][25][26] Additionally, it imposes dispersion/precipitation strengthening to the steel by forming different oxides, sulfides, and oxysulfides.…”