Research On Ultrasonic Detection Method Of Solid-liquid Interface In Space Material Science Experiment

Furnaces used for high-temperature material-associated experiments are hermetically sealed,resulting in the difficulty to observe the process of material growth inside.This hampers the data analysis on material directional solidification experiments.In addition,the difference between space microgravity environment and ground environment also poses challenges to the analysis on comparison experiments.This motivates us to propose a new kind of system to use ultrasonic nondestructive testing for identifying the location of solid-liquid interface(SLI)of metal materials in space experiments.In this thesis,I introduce the background of ultrasonic nondestructive testing including its history,current researches and research tendency.According to the existing equipment and materials in the space lab of our country,the proposed SLI detection system is built based on the technique of ultrasonic pulse echo.It provides a reliable automatic solution for multiple tasks like data collection,transportation,data processing from the samples.With the use of techniques for temperature field measurement,it would help to improve the experimental techniques used in space experiments in space labs and satellites.In the works of this thesis,I used a high-temperature furnace,ultrasonic sensors,thermocouples,and other electronic measurement systems to build an ultrasonic testing SLI system.It is able to be applied in the space experiments with some important functions like collecting the temperature data and ultrasonic data,detecting the location of SLI of metal material samples in their directional solidification process.I conducted a serious of experiments to evaluate the performance of the proposed system.The results show that the proposed system is feasible,reliable and effective to detect the location of SLI of the samples from experiments.It is anticipated that the system we built can provide new insights into the material testing in space and helps to enrich the experience regarding to the real academic experiments in our country's space lab for future.