GoGo Instruments Technology (Shanghai) Co., Ltd. specializes in temperature control technology, offering a range of patented products including probe heating/cooling stages, optical heating/cooling stages, in situ stretching stages, in situ XRD/SEM heating/cooling stages, ultra-high-temperature heating stages, and high/low-temperature test chambers, as well as testing systems for dielectric thermal spectra, electrocaloric effects, charge-discharge testing, and variable-temperature D33 measurements.

With the increasing demand for product miniaturization in microelectronics, biomedicine, and many other fields, limitations posed by the size effect on mechanical properties have drawn widespread attention from both academia and industry on how to manufacture micro-components with excellent mechanical performance. For steel alloy strips with broad application prospects, it is crucial to ensure that their micro-scale components also possess superior comprehensive mechanical properties. Analysis of domestic and international research indicates that reducing stacking fault energy and lowering deformation temperature can simultaneously enhance both strength and plasticity. However, few studies have combined research on micro-forming size effects and twinning deformation mechanisms. The deformation behavior of micro-scale materials where twinning serves as the deformation mechanism remains an unresolved research question in this field.

To address this issue, steel cast alloys with different compositions were selected, and their grain size was controlled through heat treatment processes. The tensile mechanical properties of 0.2mm thick pure copper and thin sheets of steel cast alloys with different compositions were studied. The influence of microstructure, alloy composition, and deformation temperature on the deformation behavior of the thin sheets was analyzed, aiming to reveal the mechanism of the size effect on plastic deformation in steel cast alloy sheets and to construct a constitutive model that reflects both the deformation mechanism and the size effect for sheet materials.

The GoGo Instruments Tensile Machine Heating/Cooling Stage is a product designed to be installed on a universal testing machine for studying the stress-strain properties of samples under variable temperature conditions. The product utilizes liquid nitrogen cooling and resistance heating to enable dynamic stress-strain characteristic testing of materials from -190°C to 600°C(configurable) or RT to 1500°C (configurable). It can be optionally equipped with DIC or video extensometers for high-precision strain data acquisition. The product must be used with a temperature controller and an optional cooling controller. The accompanying PC-based control software facilitates temperature setting and data acquisition, and the provided LabVIEW VIs allow customers to perform customized programming. It supports retrofitting onto various existing tensile testing machines. Samples are placed on the stage for variable temperature testing, suitable for various materials. (As shown in Figure 1)

Figure 1  GoGo Instruments Tensile Machine Heating/Cooling Stage

The GoGo Instruments Tensile Machine Heating/Cooling Stage supported tensile property testing at Harbin Institute of Technology (HIT). This customized equipment can reach a minimum temperature of -180°C to explore the impact of ultra-low temperatures on the mechanical properties of steel cast alloy sheets.

Figure 2 Cryogenic Tensile Setup

In the ultra-low temperature tensile test, the tensile specimen is fixed onto the tensile machine and placed within the cryogenic tensile device. Liquid nitrogen is introduced for cooling. After reaching the required test temperature, the temperature is maintained for a period to avoid test errors caused by temperature non-uniformity, before proceeding with the tensile test.

Figure 3 Engineering Stress-Strain Curves of Various Material Sheets at Ultra-Low Temperature (-180°C) Under Different Grain Sizes