Phase transformation and deformation behavior of a TiAl–Nb composite under quasi-static and dynamic loadings

2021 ◽  
pp. 142155
Author(s):  
Li Wang ◽  
Xiaopeng Liang ◽  
Fuqing Jiang ◽  
Sihui Ouyang ◽  
Bin Liu ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Deformation Behavior ◽  
Dynamic Loadings

Influence of Cyclic Deformation Induced Phase Transformation on the Fatigue Behavior of the Austenitic Steel X6CrNiNb1810

2014 ◽  
Vol 891-892 ◽  
pp. 1231-1236 ◽  
Author(s):  
Andreas Sorich ◽  
Marek Smaga ◽  
Dietmar Eifler
Keyword(s):  
Phase Transformation ◽  
Fatigue Life ◽  
Austenitic Steel ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Fatigue Behavior ◽  
Cyclic Hardening ◽  
Martensite Formation ◽  
Destructive Testing

The austenitic steel X6CrNiNb1810 (AISI 347) was investigated in isothermal total strain-controlled tests at ambient temperature and T = 300 °C in the LCF-and HCF-range. The phase transformation from paramagnetic austenite (fcc) into ferromagnetic α´-martensite ́(bcc) leads to cyclic hardening and to an increase in fatigue life. At 300 °C no α´-martensite formation was observed in the LCF-range and the cyclic deformation behavior depends basically on cyclic hardening processes due to an increase of the dislocation density, followed by cyclic saturation and softening due to changes in the dislocation structure. In the HCF-range an increase in fatigue life was observed due to ε- and α´-martensite formation. Measurements of the mechanical stress-strain-hysteresis as well as temperature and magnetic properties enable a characterization of the cyclic deformation behavior and phase transformation in detail. The changes in the physical data were interpreted via microstructural changes observed by scanning-and transmission-electron-microscopy as well as by x-ray investigations. Additionally electromagnetic acoustic transducers (EMATs) developed from the Fraunhofer Institute of Non-destructive Testing (IZFP) Saarbrücken were used for an in-situ characterization of the fatigue processes.

Simulation of the Interaction of Plastic Deformation in Shear Bands with Deformation-Induced Martensitic Phase Transformation in the VHCF Regime

2015 ◽  
Vol 664 ◽  
pp. 314-325 ◽  
Author(s):  
Philipp Malte Hilgendorff ◽  
Andrei Grigorescu ◽  
Martina Zimmermann ◽  
Claus Peter Fritzen ◽  
Hans Jürgen Christ
Keyword(s):  
Plastic Deformation ◽  
Phase Transformation ◽  
Deformation Behavior ◽  
Shear Bands ◽  
Martensitic Phase ◽  
Martensitic Phase Transformation ◽  
Shear Stresses ◽  
Martensite Formation ◽  
Microstructural Morphology ◽  
Microstructural Deformation

The experimental observation of the microstructural deformation behavior of a metastable austenitic stainless steel tested at the real VHCF limit indicates that plastic deformation is localized and accumulated in shear bands and martensite formation occurs at grain boundaries and intersecting shear bands. Based on these observations a microstructure-sensitive model is proposed that accounts for the accumulation of plastic deformation in shear bands (allowing irreversible plastic sliding deformation) and considers nucleation and growth of deformation-induced martensite at intersecting shear bands. The model is numerically solved using the two-dimensional (2-D) boundary element method. By using this method, real simulated 2-D microstructures can be reproduced and the microstructural deformation behavior can be investigated within the microstructural morphology. Results show that simulation of shear band evolution is in good agreement with experimental observations and that prediction of sites of deformation-induced martensite formation is possible in many cases. The analysis of simulated shear stresses in most critical slip systems under the influence of plastic deformation due to microstructural changes contributes to a better understanding of the interaction of plastic deformation in shear bands with deformation-induced martensitic phase transformation in the VHCF regime.

Deformation behavior and phase transformation of nanotwinned Al/Ti multilayers

2020 ◽  
Vol 527 ◽  
pp. 146776 ◽  
Author(s):  
Y.F. Zhang ◽  
Qiang Li ◽  
M. Gong ◽  
S. Xue ◽  
J. Ding ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Deformation Behavior

Effect of Hydrogen on Phase Transformation, Thermal Deformation Behavior, and Forming Limit of TC2 Alloy

2018 ◽  
Vol 20 (11) ◽  
pp. 1800690 ◽  
Author(s):  
Yingying Zong ◽  
Bin Shao ◽  
Xingguang Wang ◽  
Bin Guo ◽  
Debin Shan
Keyword(s):  
Phase Transformation ◽  
Deformation Behavior ◽  
Thermal Deformation ◽  
Forming Limit

Nanoindentation of Ion Implanted and Deposited Amorphous Silicon

2004 ◽  
Vol 841 ◽  
Author(s):  
J. S. Williams ◽  
B. Haberl ◽  
J. E. Bradby
Keyword(s):  
Phase Transformation ◽  
Deformation Behavior ◽  
Amorphous Film ◽  
Dominant Mode ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Si Films ◽  
Measured Hardness ◽  
Ion Implanted

ABSTRACTThe deformation behavior of both ion-implanted and deposited amorphous Si (a-Si) films has been studied using spherical nanoindentation, followed by analysis using Raman spectroscopy and cross-sectional transmission electron microscopy (XTEM). Indentation was carried out on both unannealed a-Si films (the so-called unrelaxed state) and in ion implanted films that were annealed to 450°C to fully relax the amorphous film. The dominant mode of deformation in unrelaxed films was via plastic flow of the amorphous phase rather than phase transformation, with measured hardness being typically 75–85% of that of crystalline Si. In contrast, deformation via phase transformation was clearly observed in the relaxed state of ion implanted a-Si, with the load-unload curves displaying characteristic discontinuities and Raman and XTEM indicating the presence of high-pressure crystalline phases Si-III and Si-XII following pressure release. In such cases the measured hardness was within 5% of that of the crystalline phase.

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