Quantitative Measurements of Grain Boundary Sliding in an Ultrafine-Grained Al Alloy by Atomic Force Microscopy

2011 ◽  
Vol 42 (13) ◽  
pp. 3969-3978 ◽  
Author(s):  
Jung H. Han ◽  
Farghalli A. Mohamed
2007 ◽  
Vol 345-346 ◽  
pp. 597-600
Author(s):  
Duck Young Hwang ◽  
Kion Kwon ◽  
Dong Hyuk Shin ◽  
Kyung Tae Park ◽  
Young Gun Ko ◽  
...  

Ultrafine grained (UFG) 5083 Al and 5154 Al alloys were prepared by equal channel angular pressing (ECAP) with an effective strain of ~ 4 or ~ 8. This investigation was aimed at examining the effect of the ECAP strain and post-rolling inducing different microstructure in these alloys on the deformation mechanisms at low temperature superplastic (LTS) and high strain superplastic (HSRS) regimes. The sample after 4 passes (a strain of ∼ 4) did not exhibit LTS, but superplastic elongations were obtained in the sample after 8 passes (a strain of ∼ 8). An analysis of the mechanical data in light of the standard deformation mechanisms revealed that deformation of the sample after 4 passes was governed by dislocation climb while grain boundary sliding attributed to LTS of the sample after 8 passes. In addition, the 5154 Al alloy processed by ECAP and postrolling was capable of enhancing HSRS elongation significantly. An analysis revealed that the deformation mode was changed from dislocation viscous glide to grain boundary sliding by additional ECAP strain and post-rolling.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ritabrata Dobe ◽  
Anuja Das ◽  
Rabibrata Mukherjee ◽  
Saibal Gupta

AbstractHydrous fluids play a vital role in the chemical and rheological evolution of ductile, quartz-bearing continental crust, where fluid percolation pathways are controlled by grain boundary domains. In this study, widths of grain boundary domains in seven quartzite samples metamorphosed under varying crustal conditions were investigated using Atomic Force Microscopy (AFM) which allows comparatively easy, high magnification imaging and precise width measurements. It is observed that dynamic recrystallization at higher metamorphic grades is much more efficient at reducing grain boundary widths than at lower temperature conditions. The concept of force-distance spectroscopy, applied to geological samples for the first time, allows qualitative estimation of variations in the strength of grain boundary domains. The strength of grain boundary domains is inferred to be higher in the high grade quartzites, which is supported by Kernel Average Misorientation (KAM) studies using Electron Backscatter Diffraction (EBSD). The results of the study show that quartzites deformed and metamorphosed at higher grades have narrower channels without pores and an abundance of periodically arranged bridges oriented at right angles to the length of the boundary. We conclude that grain boundary domains in quartz-rich rocks are more resistant to fluid percolation in the granulite rather than the greenschist facies.


2021 ◽  
pp. 116936
Author(s):  
Patricia Haremski ◽  
Lars Epple ◽  
Matthias Wieler ◽  
Piero Lupetin ◽  
Richard Thelen ◽  
...  

2019 ◽  
Vol 91 (16) ◽  
pp. 10557-10563 ◽  
Author(s):  
Hyonchol Kim ◽  
Kenta Ishibashi ◽  
Kosuke Matsuo ◽  
Atsushi Kira ◽  
Tomoko Okada ◽  
...  

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 272 ◽  
Author(s):  
Verónica Gallegos-Orozco ◽  
Audel Santos-Beltrán ◽  
Miriam Santos-Beltrán ◽  
Ivanovich Estrada-Guel ◽  
Iza Ronquillo-Ornelas ◽  
...  

In the present work, nanocomposites-based 3XXX series Al alloy with three different types of hard nanoparticles, including TiO2, C, and CeO2, were produced employing two techniques such as mechanical milling and stir-casting method in order to evaluate the viability of integration of the reinforcement in the Al matrix. The integration and dispersion capability of the reinforcement into the Al alloy (3xxx Series) matrix was evaluated, using a phase angle difference and surface roughness analyses by atomic force microscopy operated in both the contact mode (CM-AFM) and tapping mode (TM-AFM), respectively. The distribution profile of both rugosity and the phase angle shift was used to statically quantify the integration and dispersion of the reinforcement into the extruded samples, by using the root mean square (RMS) parameter and phase shift coupled with the events number (EN) parameter. Results from Atomic Force Microscopy (AFM) analyses were corroborated by X-ray diffractometry and scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Microhardness tests were conducted to identify the mechanical properties of the composites in the extruded condition and their correlation with the microstructure. A close relationship was found between the microstructure obtained from the AFM and X-ray diffractometry (XRD) analyses and mechanical properties. Among all, the C reinforcement produced the major changes in the microstructure as well as the best integration and dispersion into the Al-alloy coupled with the best mechanical properties.


Sign in / Sign up

Export Citation Format

Share Document