Observation of Instabilities during Plastic Deformation by in-situ SEM Indentation Experiments

2005 ◽  
Vol 7 (5) ◽  
pp. 388-392 ◽  
Author(s):  
B. Moser ◽  
J. Kuebler ◽  
H. Meinhard ◽  
W. Muster ◽  
J. Michler
Keyword(s):  
Measurement ◽  
2021 ◽  
pp. 109547
Author(s):  
Saeid Saberi ◽  
Martin Stockinger ◽  
Christian Stoeckl ◽  
Bruno Buchmayr ◽  
Helmut Weiss ◽  
...  

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6531 ◽  
Author(s):  
Zongxing Zou ◽  
Qi Zhang ◽  
Chengren Xiong ◽  
Huiming Tang ◽  
Lei Fan ◽  
...  

Slip zone soil is usually composed of clay or silty clay; in some special geological environments, it contains gravels, which make the properties of the slip zone soil more complex. Unfortunately, in many indoor shear tests, gravels are removed to meet the demands of apparatus size, and the in situ mechanical property of the gravelly slip zone soil is rarely studied. In this study, the shear mechanical property of the gravelly slip zone soil of Huangtupo landslide in the Three Gorges Reservoir area of China was investigated by the in situ shear test. The test results show that the shear deformation process of the gravelly slip zone soil includes an elastic deformation stage, elastic–plastic deformation stage, and plastic deformation stage. Four functions were introduced to express the shear constitutive model of the gravelly slip zone soil, and the asymmetric sigmoid function was demonstrated to be the optimum one to describe the relationship of the shear stress and shear displacement with a correlation coefficient of 0.986. The comparison between the in situ test and indoor direct shear test indicates that gravels increase the strength of the slip zone soil. Therefore, the shear strength parameters of the gravelly slip zone soil obtained by the in situ test are more preferable for evaluating the stability of the landslide and designing the anti-slide structures.


Author(s):  
Xiao Wang ◽  
Yuetao Zhang ◽  
Huaying Li ◽  
Ming-yu Huang

Type 316 steels have been heavily utilized as the structural material in many construction equipment and infrastructures. This paper reports the characterization of degradation in 316 austenitic stainless steel during the plastic deformation. The in-situ EBSD results revealed that, with the increase of plastic strain, the band contrast (BC) value progressively decreased in both grain and grain boundaries, and the target surface becomes uneven after the plastic tensile, which indicates that the increase of surface roughness. Meanwhile, the KAM and ρGND values are low in the origin specimen but increased significantly after the in-situ tensile. The results indicated that the KAM and ρGND are closely related to the deformation degree of the materials, which can be used as the indicator for assessing the degradation of 316 steel. Besides, the re-orientation of grain occurred after the tensile deformation, which can be recognized from the lattice orientation and local orientation maps.


2021 ◽  
Vol 4 ◽  
pp. 74-80
Author(s):  
Zhang Yong Jun ◽  
◽  
Li Xin Peng ◽  
Wang Jiu Hua ◽  
Han Jing Tao ◽  
...  

As the object for the study, graphitized high-carbon steel sheet with a carbon content of 0.66 % was used, the tensile test of this sheet using a universal testing (breaking) machine was performed; as well as in-situ observation of the microstructure in the process of tensile deformation of this sheet using in-situ technology of scanning electron microscopy (SEM) was made. The test results show that the main mechanical properties in different directions of tested graphitized high-carbon steel sheet are relatively the same, that is, for a tensile sample of different directions, the ratio of the yield strength σ0,2 to the tensile strength σв is approximately 0.73; the strain hardening index n is approximately 0.24; the plastic deformation coefficient r is approximately 0.83. This indicates that this sheet did not exhibit significant anisotropy. In the process of tensile, deformation of the specimen is mainly developed from local plastic deformation of the graphite inclusions to the total deformation in the deformation zone of the sample; with the increase of displacement, micro-gap between the graphite inclusion and ferrite grain along the direction of the axis of tensile gradually formed and propagated along the direction perpendicular to the axis of tensile; number of slip lines in the ferrite matrix gradually increased, and the distance between them gradually decreases; when the sample breaks, in the fracture large dimple with the core of graphite inclusion and small dimples in the ferrite appears. And the ferrite matrix near the fracture is covered with slip lines, this shows that the ferritic matrix underwent severe plastic deformation before breaking.


2004 ◽  
Vol 387-389 ◽  
pp. 339-342 ◽  
Author(s):  
W. Pantleon ◽  
H.F. Poulsen ◽  
J. Almer ◽  
U. Lienert

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4621
Author(s):  
Carmela Gurau ◽  
Gheorghe Gurau ◽  
Felicia Tolea ◽  
Bogdan Popescu ◽  
Mihaela Banu ◽  
...  

This work focuses on the temperature evolution of the martensitic phase ε (hexagonal close packed) induced by the severe plastic deformation via High Speed High Pressure Torsion method in Fe57Mn27Si11Cr5 (at %) alloy. The iron rich alloy crystalline structure, magnetic and transport properties were investigated on samples subjected to room temperature High Speed High Pressure Torsion incorporating 1.86 degree of deformation and also hot-compression. Thermo-resistivity as well as thermomagnetic measurements indicate an antiferromagnetic behavior with the Néel temperature (TN) around 244 K, directly related to the austenitic γ-phase. The sudden increase of the resistivity on cooling below the Néel temperature can be explained by an increased phonon-electron interaction. In-situ magnetic and electric transport measurements up to 900 K are equivalent to thermal treatments and lead to the appearance of the bcc-ferrite-like type phase, to the detriment of the ε(hcp) martensite and the γ (fcc) austenite phases.


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