## 1 Introduction  
Lubrication systems in aero-engines are used to lubricate and cool bearings, gears, and splines to ensure a high level of safety and reliability for the aircraft even after long periods of operation [1]. One of the important components for storing the lubricating oil is the lubricating oil tank, which is fixed to the aero-engine casing by mounting structures. As shown in Figure 1, the installation arrangement of the lubricating oil tank on an AL-31 FN aero-engine. Strong external vibrations of the aero-engine can cause vibration damage or faults in the lubricating oil tank and its mounting structure during services. Therefore, the reasonable vibration reduction of the lubricating oil tank is urgent. Traditional vibration reduction methods, such as adding damping devices, are often difficult to meet the requirements of equipment miniaturisation and lightweight [2]. On the contrary, the damping materials can be used to manufacture aero-engine components to reduce vibration at the source [3]. High damping alloys absorb external vibration energy through a variety of damping mechanisms within the material and convert it into thermal energy [4], thus generating internal dissipation to reduce the vibration and noise. High damping alloys are a novel class of functional structural materials that have been used in marine propellers, aircraft, machine tools, gears, fasteners, and other fields, and the application prospects are very promising [5, 6]. High damping alloy materials can not only reduce the noise generated by machinery and its components but also absorb the damping energy [7], so that the vibration is extremely fast reduced, avoiding the fatigue damage caused by the intense vibration and prolonging the life of the machine parts. High damping alloy materials used for engineering applications should have as much as possible high damping, high strength, easy manufacturing, a large application range, low cost, and other comprehensive performance. According to the generation mechanism of damping, high-damping alloys are mainly divided into several categories, such as multiphase damping alloys (grey cast iron, Zn-Al), dislocation damping alloys (Mg-system alloys), twinned damping alloys (Mn-Cu), and ferromagnetic damping alloys (Fe-Cr-Mo, Fe-Cr-Al) [8]. Among them, ferromagnetic damping alloys are ferrite-based high-damping alloy materials with alloying elements such as Cr, Al, Mo, Ni, and Co. For example, the composition of Silentalloy is Fe-12 Cr-3 Al; the composition of Gentalloy has Fe-W, Fe-Mo, and Fe-Mo-Cr; and Fe-Co, Fe-Co-Cr and other iron-based high damping alloy materials. The main damping mechanism of ferromagnetic damping alloy is associated with magneto-mechanical damping, that is, when the external stress is applied, the internal magnetic domain in the material will slip and rotate, which will consume energy and, therefore, exhibit a high damping effect [9]. If the alloy is subjected to cyclic external forces, the alloy exhibits internal depletion [10]. Ferromagnetic high damping alloy materials are the most widely used high damping alloy materials due to their excellent plastic manufacturing performance, easy surface hardening, damping coefficients that are independent of frequency, high service temperatures, good mechanical properties, and high damping performance [11], as well as cheaper prices. There are fewer applied types of research on Fe-Al alloys; the research on ferromagnetic high damping alloys mainly focuses on Fe-Cr alloys and has obtained some results. For example, the U.S. Naval Institute [12] studies the Vacrosil-010 alloy, and results show that this type of alloy has superior vibration and noise reduction characteristics. The ship gear box base with this material can make a noise reduction of 10 dB compared to the conventional steel material base. [PERSON] [13] studied the damping capacity of ferromagnetic Fe-Cr alloys containing 0-8% Al and 0-4% Mo, and the results show that lower concentrations of Al and Mo can increase the damping of the alloys by several times.