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Unique mechanical properties of nanostructured transparent MgAl2O4 ceramics.

Zhang J, Lu T, Chang X, Wei N, Qi J - Nanoscale Res Lett (2013)

Bottom Line: These tests were carried out on samples at different applied loads ranging from 300 to 9,000 μN.The elastic recovery for nanostructured transparent MgAl2O4 ceramics at different applied loads was derived from the force-depth data.Finally, the experimentally measured hardness and Young's modulus, as derived from the load-displacement data, are as high as 31.7 and 314 GPa, respectively.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, People's Republic of China. zhjie126@126.com.

ABSTRACT
Nanoindentation tests were performed on nanostructured transparent magnesium aluminate (MgAl2O4) ceramics to determine their mechanical properties. These tests were carried out on samples at different applied loads ranging from 300 to 9,000 μN. The elastic recovery for nanostructured transparent MgAl2O4 ceramics at different applied loads was derived from the force-depth data. The results reveal a remarkable enhancement in plastic deformation as the applied load increases from 300 to 9,000 μN. After the nanoindetation tests, scanning probe microscope images show no cracking in nanostructured transparent MgAl2O4 ceramics, which confirms the absence of any cracks and fractures around the indentation. Interestingly, the flow of the material along the edges of indent impressions is clearly presented, which is attributed to the dislocation introduced. High-resolution transmission electron microscopy observation indicates the presence of dislocations along the grain boundary, suggesting that the generation and interaction of dislocations play an important role in the plastic deformation of nanostructured transparent ceramics. Finally, the experimentally measured hardness and Young's modulus, as derived from the load-displacement data, are as high as 31.7 and 314 GPa, respectively.

No MeSH data available.


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HRTEM image of the nanostructured transparent MgAl2O4 ceramic. Inset shows the selected area diffraction pattern.
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Figure 3: HRTEM image of the nanostructured transparent MgAl2O4 ceramic. Inset shows the selected area diffraction pattern.

Mentions: In order to further investigate the mechanical properties of nanostructured transparent ceramics, we used HRTEM to examine the microstructures of the sample indented at 9,000 μN. The HRTEM image is shown in Figure 3. The inset in this figure is a selected area electron diffraction pattern of the indented sample, indicative of a magnesia-alumina spinel crystal structure. The left part of the HRTEM image reveals well-ordered atomic structures. However, there are dislocations close to the triangular grain boundary, suggesting that the generation, movement, and interaction of dislocations during the indentation play an important role in the plastic deformation as well as the resulting mechanical properties.


Unique mechanical properties of nanostructured transparent MgAl2O4 ceramics.

Zhang J, Lu T, Chang X, Wei N, Qi J - Nanoscale Res Lett (2013)

HRTEM image of the nanostructured transparent MgAl2O4 ceramic. Inset shows the selected area diffraction pattern.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3672023&req=5

Figure 3: HRTEM image of the nanostructured transparent MgAl2O4 ceramic. Inset shows the selected area diffraction pattern.
Mentions: In order to further investigate the mechanical properties of nanostructured transparent ceramics, we used HRTEM to examine the microstructures of the sample indented at 9,000 μN. The HRTEM image is shown in Figure 3. The inset in this figure is a selected area electron diffraction pattern of the indented sample, indicative of a magnesia-alumina spinel crystal structure. The left part of the HRTEM image reveals well-ordered atomic structures. However, there are dislocations close to the triangular grain boundary, suggesting that the generation, movement, and interaction of dislocations during the indentation play an important role in the plastic deformation as well as the resulting mechanical properties.

Bottom Line: These tests were carried out on samples at different applied loads ranging from 300 to 9,000 μN.The elastic recovery for nanostructured transparent MgAl2O4 ceramics at different applied loads was derived from the force-depth data.Finally, the experimentally measured hardness and Young's modulus, as derived from the load-displacement data, are as high as 31.7 and 314 GPa, respectively.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, People's Republic of China. zhjie126@126.com.

ABSTRACT
Nanoindentation tests were performed on nanostructured transparent magnesium aluminate (MgAl2O4) ceramics to determine their mechanical properties. These tests were carried out on samples at different applied loads ranging from 300 to 9,000 μN. The elastic recovery for nanostructured transparent MgAl2O4 ceramics at different applied loads was derived from the force-depth data. The results reveal a remarkable enhancement in plastic deformation as the applied load increases from 300 to 9,000 μN. After the nanoindetation tests, scanning probe microscope images show no cracking in nanostructured transparent MgAl2O4 ceramics, which confirms the absence of any cracks and fractures around the indentation. Interestingly, the flow of the material along the edges of indent impressions is clearly presented, which is attributed to the dislocation introduced. High-resolution transmission electron microscopy observation indicates the presence of dislocations along the grain boundary, suggesting that the generation and interaction of dislocations play an important role in the plastic deformation of nanostructured transparent ceramics. Finally, the experimentally measured hardness and Young's modulus, as derived from the load-displacement data, are as high as 31.7 and 314 GPa, respectively.

No MeSH data available.


Related in: MedlinePlus