Elevated temperature evaluation
Research materials: Single element metals, NiMoW alloy, Shape memory alloys (SMAs), etc.
Testing of small-scale materials has historically been challenging due to the inherent difficulties associated with handling and gripping of the samples. It becomes even challenging when we try to test small-scale materials in extreme conditions. For example, the basic requirement for accurate elevated temperature mechanical testing, including a uniform temperature distribution throughout the sample, accurate measurement of temperature, and a controlled environment to prevent sample oxidation, are further complicated by small sample dimensions. As a result, only few studies reported the mechanical testing of freestanding thin films at elevated temperatures.
For testing sub-micron thick thin films at elevated temperature, we utilize the in situ high temperature nanoindenter and have built a micro-tensile tester with 9.7µN load resolution and 10nm displacement resolution that can be used inside a scanning electron microscope (SEM). Measurements at elevated temperatures were performed through use of two silicon-based micromachined heaters that support the sample. Each heater consists of a tungsten heating element that also serves as a temperature gauge. To demonstrate the testing capabilities, tensile tests were performed on sub-micron Cu and Au films at various temperatures up to 430 ℃, and up to 743 ℃ for ZrB2 films. Stress-strain curves show a significant decrease in yield strength and initial slope for the samples tested at elevated temperature, which we attribute to diffusion facilitated grain boundary sliding and dislocation climb.
Moreover, to accustom the necessities of understanding material behaviors in elevated temperatures when the characteristic dimensions are scaled up, both of our custom-built meso-scale tester and universal tensile tester is equipped with our custom-built furnace for high temperature testing.
Testing of small-scale materials has historically been challenging due to the inherent difficulties associated with handling and gripping of the samples. It becomes even challenging when we try to test small-scale materials in extreme conditions. For example, the basic requirement for accurate elevated temperature mechanical testing, including a uniform temperature distribution throughout the sample, accurate measurement of temperature, and a controlled environment to prevent sample oxidation, are further complicated by small sample dimensions. As a result, only few studies reported the mechanical testing of freestanding thin films at elevated temperatures.
For testing sub-micron thick thin films at elevated temperature, we utilize the in situ high temperature nanoindenter and have built a micro-tensile tester with 9.7µN load resolution and 10nm displacement resolution that can be used inside a scanning electron microscope (SEM). Measurements at elevated temperatures were performed through use of two silicon-based micromachined heaters that support the sample. Each heater consists of a tungsten heating element that also serves as a temperature gauge. To demonstrate the testing capabilities, tensile tests were performed on sub-micron Cu and Au films at various temperatures up to 430 ℃, and up to 743 ℃ for ZrB2 films. Stress-strain curves show a significant decrease in yield strength and initial slope for the samples tested at elevated temperature, which we attribute to diffusion facilitated grain boundary sliding and dislocation climb.
Moreover, to accustom the necessities of understanding material behaviors in elevated temperatures when the characteristic dimensions are scaled up, both of our custom-built meso-scale tester and universal tensile tester is equipped with our custom-built furnace for high temperature testing.
Read more in our publications:
[1] Tekoğlu, E., O'Brien, A. D., Bae, J. S., Lim, K. H., Liu, J., Kavak, S., ... & Li, J. (2023). Metal matrix composite with superior ductility at 800° C: 3D printed In718+ ZrB2 by laser powder bed fusion. Composites Part B: Engineering, 111052.
[2] Lim, K. H., Ryou, K., Choi, J. H., Choi, G., Choi, W. S., Lee, J. H., ... & Sim, G. D. (2023). Effect of titanium nitride inclusions on the mechanical properties of direct laser deposited Inconel 718. Extreme Mechanics Letters, 61, 102009.
[3] Sim, G. D., Choi, Y. S., Lee, D., Oh, K. H., & Vlassak, J. J. (2016). High tensile strength of sputter-deposited ZrB2 ceramic thin films measured up to 1016 K. Acta Materialia, 113, 32-40.
[4] Sim, G. D., & Vlassak, J. J. (2014). High-temperature tensile behavior of freestanding Au thin films. Scripta Materialia, 75, 34-37.
[5] Sim, G. D., Park, J. H., Uchic, M. D., Shade, P. A., Lee, S. B., & Vlassak, J. J. (2013). An apparatus for performing microtensile tests at elevated temperatures inside a scanning electron microscope. Acta materialia, 61(19), 7500-7510.
[1] Tekoğlu, E., O'Brien, A. D., Bae, J. S., Lim, K. H., Liu, J., Kavak, S., ... & Li, J. (2023). Metal matrix composite with superior ductility at 800° C: 3D printed In718+ ZrB2 by laser powder bed fusion. Composites Part B: Engineering, 111052.
[2] Lim, K. H., Ryou, K., Choi, J. H., Choi, G., Choi, W. S., Lee, J. H., ... & Sim, G. D. (2023). Effect of titanium nitride inclusions on the mechanical properties of direct laser deposited Inconel 718. Extreme Mechanics Letters, 61, 102009.
[3] Sim, G. D., Choi, Y. S., Lee, D., Oh, K. H., & Vlassak, J. J. (2016). High tensile strength of sputter-deposited ZrB2 ceramic thin films measured up to 1016 K. Acta Materialia, 113, 32-40.
[4] Sim, G. D., & Vlassak, J. J. (2014). High-temperature tensile behavior of freestanding Au thin films. Scripta Materialia, 75, 34-37.
[5] Sim, G. D., Park, J. H., Uchic, M. D., Shade, P. A., Lee, S. B., & Vlassak, J. J. (2013). An apparatus for performing microtensile tests at elevated temperatures inside a scanning electron microscope. Acta materialia, 61(19), 7500-7510.
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Updated on 2025.04.05
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