Cryogenic System Based on a Pulse Tube Cryocooler for Testing Tensile Properties of Micro-Sized Materials

For testing tensile properties of materials at cryogenic temperature, it is important to create a cryogenic environment. In this study, a cryogenic system has been designed and established for testing tensile properties of micro-sized materials. A pulse tube cryocooler (PTC) is used as cold source. The temperature of the sample can be controlled and maintained within range from 300 K and 77 K. The volume and weight of the system is only about 0.5 m3 and 25 kg respectively. First, for testing micro-sized materials, the structure of the system is designed, which consists of the cooling system, the mechanical testing system and the data collection system. And then the heat leakage of the system is calculated and analyzed. According to the optimal result of simulated calculation, the cryocooler with the cooling capacity of 3 W at 77 K was selected as the cold source of the system. Finally, the experiments are performed on testing the cooling performance of this system by the controlling system, including the cooling process of the PTC and the sample chamber. The results show that the lowest temperatures of the cold end are 50 K and 63 K respectively within no-load cooling and mechanical module assembled cooling, which is proved that the system can test tensile properties of the micro-sized sample from 77 K to 300 K.