TY - JOUR
T1 - A novel method for In Situ electromechanical characterization of nanoscale specimens
AU - Reid, Russell C.
AU - Piqué, Alberto
AU - Kang, Wonmo
N1 - Funding Information:
This work was supported by the ASEE-NRL postdoctoral fellowship and the Office of Naval Research through the US Naval Research Laboratory's Basic Research Program. The authors thank C. Kindle at NRL for his technical support.
Publisher Copyright:
© 2017 Journal of Visualized Experiments.
PY - 2017/6/2
Y1 - 2017/6/2
N2 - Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and forging. Adoption of this technique is proceeding despite disagreement concerning the underlying mechanism responsible for EAD. The experimental procedure described herein enables a more explicit study compared to previous EAD research by removing thermal effects, which are responsible for disagreement in interpreting previous EAD results. Furthermore, as the procedure described here enables EAD observation in situ and in real time in a transmission electron microscope (TEM), it is superior to existing post-mortem methods that observe EAD effects post-test. Test samples consist of a single crystal copper (SCC) foil having a free-standing tensile test section of nanoscale thickness, fabricated using a combination of laser and ion beam milling. The SCC is mounted to an etched silicon base that provides mechanical support and electrical isolation while serving as a heat sink. Using this geometry, even at high current density (~3,500 A/mm2), the test section experiences a negligible temperature increase (<0.02 °C), thus eliminating Joule heating effects. Monitoring material deformation and identifying the corresponding changes to microstructures, e.g. dislocations, are accomplished by acquiring and analyzing a series of TEM images. Our sample preparation and in situ experiment procedures are robust and versatile as they can be readily utilized to test materials with different microstructures, e.g., single and polycrystalline copper.
AB - Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and forging. Adoption of this technique is proceeding despite disagreement concerning the underlying mechanism responsible for EAD. The experimental procedure described herein enables a more explicit study compared to previous EAD research by removing thermal effects, which are responsible for disagreement in interpreting previous EAD results. Furthermore, as the procedure described here enables EAD observation in situ and in real time in a transmission electron microscope (TEM), it is superior to existing post-mortem methods that observe EAD effects post-test. Test samples consist of a single crystal copper (SCC) foil having a free-standing tensile test section of nanoscale thickness, fabricated using a combination of laser and ion beam milling. The SCC is mounted to an etched silicon base that provides mechanical support and electrical isolation while serving as a heat sink. Using this geometry, even at high current density (~3,500 A/mm2), the test section experiences a negligible temperature increase (<0.02 °C), thus eliminating Joule heating effects. Monitoring material deformation and identifying the corresponding changes to microstructures, e.g. dislocations, are accomplished by acquiring and analyzing a series of TEM images. Our sample preparation and in situ experiment procedures are robust and versatile as they can be readily utilized to test materials with different microstructures, e.g., single and polycrystalline copper.
KW - Electromechanical behavior
KW - Engineering
KW - In situ material characterization
KW - Issue 124
KW - Laser patterning
KW - Microsystem
KW - Nanospecimens
KW - Transmission electron microscopy
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U2 - 10.3791/55735
DO - 10.3791/55735
M3 - Article
C2 - 28605394
AN - SCOPUS:85021219456
SN - 1940-087X
VL - 2017
JO - Journal of Visualized Experiments
JF - Journal of Visualized Experiments
IS - 124
M1 - e55735
ER -