New aviation materials take advantage of the trend, tungsten and molybdenum consumption is expected to increase
In the 21st century, aviation materials are developing in the direction of high performance, high function, multi-function, integration of structure and function, compound, intelligence, low cost and compatibility with environment. As one of the key materials for aviation components, consumption of tungsten and molybdenum products is expected to increase.
Airframe material
The high altitude, high speed and high mobility capability of fighter requires that the structural materials of the aircraft must ensure sufficient strength and stiffness performance, which means that the fuselage materials should have a greater capacity to bear the payload. Titanium and composite materials are slowly replacing steel and aluminum as aircraft structures.
In addition, the fuselage material should be less weight and good stealth. The reduced weight of the structure means that it can carry more fuel or other payloads, which not only increases the distance flown but also increases the cost per unit weight of the structure, making titanium alloys and composites more suitable for aircraft structures than steel and aluminum. For stealth, aircraft Windows can be made from tungsten trioxide (WO3) nano-powders.
WO3 is an important semiconductor material with excellent electrochromic and photochromic properties, so the light inside the cabin will be softer, day or night, and the view from the window will be less brilliant.
Engine materials
High temperature resistance is the main development direction of this material. When the turbine inlet temperature of the engine is increased from 1300K to 1610K, the turbine output efficiency can be increased from 46.40% to 51.60%.This requires that the engine material should be upgraded, using high temperature alloy. In modern aero-engines, the amount of superalloy accounts for 40% ~ 60% of the total weight of the engine.
One way to find advanced heat resistant alloys is to base them on a metal with a high melting point, such as molybdenum. Although the melting point of molybdenum (2622℃) is lower than that of tungsten (3410℃), it is more suitable for use in aero-engines because the specific gravity of molybdenum is 10.22g/cm3 and that of tungsten is 19.3g/cm3.
The results show that the high temperature resistance of molybdenum alloy is superior to that of nickel base alloy and cobalt base alloy. In addition, molybdenum also has good thermal conductivity, so it is more conducive to the manufacture of high temperature parts. Because the combustion chamber, guide, turbine blade, turbine disc and other components in the aero engine are often in an uneven hot and cold environment, if the thermal conductivity of the material is not good, it will be easy to fracture the parts due to thermal stress.
In addition to the above two aviation parts need to be made of tungsten molybdenum, aircraft heat shield can also be made of tungsten plate, to prevent heat transfer; The load bearing components are sprayed with tungsten carbide coating, which can prolong the service life and improve the reliability; Tungsten alloy counterweight block, can reduce the occurrence of safety accidents and improve transport efficiency; Tungsten-molybdenum sulfide used in sliding parts can effectively reduce the wear rate.
According to industry forecasts, 40,664 new aircraft, valued at about $5.96 trillion, will be delivered globally between 2020 and 2039 to replace and support fleet development. Among them, China will deliver 8,725 new aircraft, or 21.41% of the twin-aisle aircraft, a total of 1,868 aircraft; Single aisle passenger aircraft accounted for 68.05%, a total of 5,937;The remaining 10.54% were 920 regional jets.
It can be seen that there will be a huge demand space for aviation materials in the future, which will surely drive the consumption of tungsten and molybdenum related materials of upstream products.
