TANIST – Tescan and Newtec In situ Testing System

SEM-based in situ testing systems have been gaining significant attention across various research disciplines in recent years as real-time observation of dynamic mechanical, thermal, and chemical phenomena become increasingly important. Traditionally, these methods required complex and time-consuming sample preparation, as well as constant operator supervision. However, with the rising demand for higher spatial and temporal resolution, automation has become critical in reducing reliance on the operator while at the same time improving experimental efficiency.

Most SEM-based in situ mechanical testing techniques are designed for FIB-fabricated micron-scale specimens, which are well-suited for studying deformation mechanisms in single-crystalline materials or a limited number of crystals. While this approach simplifies the problem and provides fundamental insights into deformation mechanisms, it may also obscure critical microstructural interactions by limiting analysis to a small number of crystals.

TANIST Hardware

The TESCAN and Newtec In Situ Testing (TANIST) system (figure 1) is designed to overcome these challenges. Currently operating at Monash Centre for Electron Microscopy (MCEM), TANIST consists of a TESCAN Clara Field-Free analytical ultra-high-resolution SEM, integrated with Newtec Scientific’s in situ thermo-mechanical and heating stages. These include the MT1000 for thermo-mechanical testing and FurnaSEM for high-temperature heating experiments. Additionally, the system features a vacuum chamber referred to as the exo-SEM, which enables thermal and mechanical testing in an in situ optical configuration, outside the SEM.

Figure 1. TANIST in situ testing system at Monash Centre for Electron Microscopy (MCEM).

System Automation

A key advantage of TANIST is its robust automation, made possible by seamless communication between the Newtec software, the TESCAN computer, and the Oxford Instruments system. The Newtec computer, running SoftStrain for the MT1000 stage and FurnaSEM for the FurnaSEM stage, takes control of critical SEM functions, including the microscope stage, beam parameters, in-column and in-chamber detectors, and Oxford EBSD and EDS detectors. This automation enables:

• Automated focus and astigmatism correction after each temperature or strain increment
• Real-time tracking of the region of interest (ROI), keeping it centered in the field of view throughout heating or loading experiments
• Automated insertion and retraction of detectors, depending on the requirements of each experimental stage

By significantly reducing the need for continuous operator presence, TANIST minimizes human error while enhancing the precision and efficiency of high-throughput in-situ SEM experiments.

System Specifications

Table 1 provides a comprehensive overview of the system’s specifications.

Module	Specification	Value
MT1000 - In Situ thermo-mechanical stage	Mechanical Loading
	Max. Load	10,000N
	Max. Loading Rate	20 N/s
	Loading configurations	Tensile, compression, bending
	Max. Temp.	1000°C
	Heating / Cooling
	Max. Temp.	1000°C
	Max. Heating Rate	2°C/s
	Heating Modes	Homogeneous, differential
	Min. Temp.	-150°C
	Other
	Gas Injection	Yes
	Detector Compatibility	EBSD, EDS, BSE, ETD
FurnaSEM - In Situ thermal stage	Heating
	Max. Temp.	1200°C
	Max. Heating Rate	1°C/s
	Heating
	Gas Injection	Yes
	Detector Compatability	EBSD, EDS, BSE, ETD

Figure 2 shows the the TANIST set up at MCEM, the MT1000 and FurnaSEM stages and the ExoSEM chamber. As described in Table 1, in addition to mechanical testing at room and elevated temperatures, the MT1000 stage also offers mechanical testing at cryogenic temperatures. The MT1000 stage boasts distinctive and critical advantages that set it apart. For instance, its low-power heaters minimise thermal emission allowing for uninterrupted high-temperature imaging and analysis without “blinding” the detectors. Another key advantage is the exceptional versatility in experiment design, enabling scenarios such as creating a temperature gradient across the specimen (i.e. differential heating).

Figure 2d. An image of the inside of the CLARA SEM showing the MT1000 stage in an EBSD configuration at elevated temperatures with the EBSD detector inserted into position

Furthermore, it has been shown that the deposition of a speckle pattern on the mechanical specimens allows for the conduction of in situ High Resolution Digital Image Correlation (HRDIC) experiments using the MT1000 stage. In fact, we have conducted in situ HRDIC experiments combined with EBSD to correlate the localised strains with the phases and their crystallographic orientation. In these experiments the speckle patterns were developed using a gold remodelling process described elsewhere [1, 2]. Moreover, recent experiments performed on 316 stainless steel specimens, have illustrated the promising capacity of the MT1000 stage in performing in situ electron channelling contrast imaging (ECCI).

Thermal and Mechanical Testing in Different Gases

Both the MT1000 and the FurnaSEM stages offer the possibility of introducing different gases onto the specimen during the mechanical, heating or cryogenic tests. This is possible thanks to the great control over the gas flow rate as well as the low vacuum compatibility of the TESCAN Clara SEM.

The compatibility of the Newtec software with all commonly available detectors in the SEM allows for the generation of multifaceted datasets by using different detectors at different stages of the experiment.

References

1.           Yavuzyegit, B., et al., Mapping plastic deformation mechanisms in AZ31 magnesium alloy at the nanoscale. Acta Materialia, 2023. 250: p. 118876.

2.           Orozco-Caballero, A., et al., How magnesium accommodates local deformation incompatibility: A high-resolution digital image correlation study. Acta Materialia, 2017. 133: p. 367-379.

Learn More

To learn more about how the TANIST system can be used and work that has been performed watch this on-demand webinar.