## 1 Introduction  
Within the elastic limit, the stress and strain of an elastic body become directly proportional, and its ratio is called elastic modulus, also known as Young's modulus or tensile modulus. Macroscopically, elastic modulus indicates the ability of solid material to resist deformation. Microscopically, the elastic modulus reflects the strength of the bond between atoms. In engineering application, the elastic modulus of materials plays an important role in the application, modification and microstructure study of materials. No matter studying the static or dynamic characteristics of mechanical components [1], the measurement of elastic modulus is of great significance for studying the mechanical properties, state and life of materials [2, 3]. The size of elastic modulus is related to the type of material, temperature and other factors [4]. With the continuous progress of technology, all kinds of machinery and precision instruments have higher and higher requirements for the mechanical properties of materials, which put forward higher requirements for accurately measuring the elastic modulus of different materials in different application environments. In general, both the resonance method and the static method can measure the elastic modulus of the material [5, 6, 7]. Resonance method is suitable for measuring samples with large elastic modulus, and can also be applied to measure the elastic modulus of materials at high temperature [8, 9]. In 2013, [PERSON] et al. [10] used the resonance method to measure the elastic modulus of fireproof concrete materials at different temperatures, and re-established the relationship curve between the characteristics of high-temperaturefireproof materials and temperature changes. In 2019, [PERSON] et al. [11] measured the change of elastic modulus of aluminum ceramic materials during heating and cooling. The static method is suitable for measuring materials with large elongation, but it is difficult to measure brittle materials and materials at different temperatures. The key of this method is to detect the micro-shape of material caused by external force. At present, the measurement methods of material microform variables mainly include optical measurement, electrical measurement and so on. Optical measurement methods [12; 13; 14; 15; 16; 17; 18; 19] include optical lever method [12], diffraction method [13; 14], digital optical speckle method [15; 16], etc. The principle of electrical measurement is that when the size of metal material changes, its resistance value also changes. In this way, by measuring the change of resistance, the micro-shape variable of the sample can be calculated. Because electrical measurement depends on the conductivity of the material, this method is only suitable for metal materials. In contrast, the static tensile test device used in this paper has the advantages of simple structure and operation, stable performance and high precision. It has wide application value in designing all kinds of testing instruments. Ultrasonic testing is an important nondestructive testing technology. It can evaluate the properties and defects of materials [20; 21; 22] by detecting the changes of reflected or transmitted ultrasonic wave signals. [PERSON] et al. [23] detected the creep characteristics of Nimonic C263, and analyzed the creep deformation behavior and fracture mechanism of nickel-based superalloy. [PERSON] et al. [24] used ultrasonic phased array method to measure the propagation velocity of ultrasonic in brass, and then calculated the elastic modulus of brass. [PERSON] et al. [25] measured the static and dynamic elastic moduli of AAS composites, and carried out ultrasonic characterization of the elastic moduli and compressive strength properties of the materials. The traditional ultrasonic testing technology needs to fill the coupling agent between the ultrasonic transducer and the sample to realize the effective propagation of acoustic signal when measuring elastic modulus.