Strain rate sensitivity of hydrogen-assisted ε-martensitic transformation and associated hydrogen embrittlement in high-Mn steel

2021 ◽  
Author(s):  
Chunxi Hao ◽  
Motomichi Koyama ◽  
Saya Ajito ◽  
Eiji Akiyama
Keyword(s):  
Martensitic Transformation ◽  
Hydrogen Embrittlement ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Mn Steel

An Evaluation on Strain Dependency and Strain Rate Sensitivity of Martensitic Transformation Generated in TRIP Steel by Measurement of Magnetic Permeability

2014 ◽  
Vol 626 ◽  
pp. 432-437
Author(s):  
Yutaro Moriyama ◽  
Daiki Inoshita ◽  
Takeshi Iwamoto
Keyword(s):  
Mechanical Properties ◽  
Martensitic Transformation ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Magnetic Permeability ◽  
Trip Steel ◽  
Shock Absorber ◽  
Rate Sensitivity ◽  
Volume Resistivity ◽  
Relative Magnetic Permeability

If TRIP steel with excellent mechanical properties dominated by strain induced martensitic transformation (SIMT) can be applied to a shock absorber in automobiles, it becomes possible to reduce a weight of the automobiles by decreasing the thickness of their components. In order to improve its reliability by clarification of the mechanical properties, it is necessary to evaluate continuous evolution of martensite during deformation in TRIP steel. In the previous studies, volume resistivity and impedance have been measured during deformation. However, these studies have not been succeeded for the evaluation of martensite with higher precision. Here, because of focusing on a characteristic which martensite indicates ferromagnetism, the evolution of martensite is evaluated by measuring relative magnetic permeability in TRIP steel during deformation at various strain rate.

scholarly journals Negative Strain Rate Sensitivity Induced by Structure Heterogeneity in Zr64.13Cu15.75Ni10.12Al10 Bulk Metallic Glass

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 339
Author(s):  
Xiang Wang ◽  
Zhi Qiang Ren ◽  
Wei Xiong ◽  
Si Nan Liu ◽  
Ying Liu ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Strain Rate ◽  
Bulk Metallic Glass ◽  
Strain Rate Sensitivity ◽  
Critical Role ◽  
Rate Sensitivity ◽  
Confined Compression ◽  
Negative Strain Rate Sensitivity ◽  
Cast Specimen ◽  
Structure Heterogeneity

The negative strain rate sensitivity (SRS) of metallic glasses is frequently observed. However, the physical essence involved is still not well understood. In the present work, small-angle X-ray scattering (SAXS) and high-resolution transmission electron microscopy (HRTEM) reveal the strong structure heterogeneity at nanometer and tens of nanometer scales, respectively, in bulk metallic glass (BMG) Zr64.13Cu15.75Ni10.12Al10 subjected to fully confined compression processing. A transition of SRS of stress, from 0.012 in the as-cast specimen to −0.005 in compression processed specimen, was observed through nanoindentation. A qualitative formulation clarifies the critical role of internal stress induced by structural heterogeneity in this transition. It reveals the physical origin of this negative SRS frequently reported in structurally heterogeneous BMG alloys and its composites.

Strain rate sensitivity of a 1.5 GPa nanotwinned steel

2021 ◽  
Author(s):  
R.D. Liu ◽  
Y.Z. Li ◽  
L. Lin ◽  
C.P. Huang ◽  
Z.H. Cao ◽  
...  
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity

scholarly journals The Strain Rate Sensitivity and Creep Behavior for the Tripler Plane of Potassium Dihydrogen Phosphate Crystal by Nanoindentation

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 369
Author(s):  
Jianhui Mao ◽  
Wenjun Liu ◽  
Dongfang Li ◽  
Chenkai Zhang ◽  
Yi Ma
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Creep Deformation ◽  
Potassium Dihydrogen Phosphate ◽  
Rate Sensitivity ◽  
Dislocation Nucleation ◽  
Machining Process ◽  
Dihydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
Kdp Crystals

As an excellent multifunctional single crystal, potassium dihydrogen phosphate (KDP) is a well-known, difficult-to-process material for its soft-brittle and deliquescent nature. The surface mechanical properties are critical to the machining process; however, the characteristics of deformation behavior for KDP crystals have not been well studied. In this work, the strain rate effect on hardness was investigated on the mechanically polished tripler plane of a KDP crystal relying on nanoindentation technology. By increasing the strain rate from 0.001 to 0.1 s−1, hardness increased from 1.67 to 2.07 GPa. Hence, the strain rate sensitivity was determined as 0.053, and the activation volume of dislocation nucleation was 169 Å3. Based on the constant load-holding method, creep deformation was studied at various holding depths at room temperature. Under the spherical tip, creep deformation could be greatly enhanced with increasing holding depth, which was mainly due to the enlarged holding strain. Under the self-similar Berkovich indenter, creep strain could be reduced at a deeper location. Such an indentation size effect on creep deformation was firstly reported for KDP crystals. The strain rate sensitivity of the steady-state creep flow was estimated, and the creep mechanism was qualitatively discussed.

Nanoindentation strain rate sensitivity of thermo-oxidized PMR-15 polyimide

2009 ◽  
Vol 44 (8) ◽  
pp. 2119-2127 ◽  
Author(s):  
Y. C. Lu ◽  
G. P. Tandon ◽  
S. Putthanarat ◽  
G. A. Schoeppner
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity
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