Development of <i>In Situ</i> Fatigue Performance Testing Apparatus for Materials Under Coupling Conditions of High-Temperature and Combined Mechanical Loads
Jiucheng Zhao, Shizhong Zhang, Wan Qi Jie, Lixia Xu, Liming Zhou, Zhichao Ma, Zhuang Ren, Yuan Mou, Hongwei Zhao
Abstract
In order to study the high-cycle and very-high-cycle fatigue performance of aero-engine blade materials under conditions close to their real service, an in situ fatigue performance testing apparatus for materials under coupling conditions of high-temperature and combined mechanical loads (HTCMFTA) has been developed. The main functions of the apparatus includes: static loads loading, ultrasonic fatigue (up to 20 kHz) loading, high-temperature field (up to 1100°C) building, and in situ monitoring. A series of tests on the compressor blade material Ti-6Al-4V alloy under coupling conditions of high-temperature and combined mechanical loads were carried out with the apparatus. The results show that the apparatus can accurately simulate various mechanical loads and high-temperature fields to which the blade materials are subjected. The static and dynamic mechanical properties of Ti-6Al-4V alloy under high-temperature and combined mechanical loads were also revealed. The results show that there is a synergistic effect between tension and bending, as the pre-tension stress increases, the bending stiffness and bending-bearing capacity of Ti-6Al-4V alloy were enhanced. A coupling effect exists between temperature, tension, and bending. Under the combined loads, the bending stiffness of Ti-6Al-4V alloy slightly weakened with the increase of temperature, but the bending-bearing capacity increased significantly. This apparatus has important practical significance and scientific value for studying the high-cycle and very-high-cycle fatigue performance of aero-engine blade materials and ensuring its service safety.