Advantages of using titanium alloy materials in fasteners

As an important general basic component, fasteners play a vital role in industry and are known as the "rice of industry". With the development of my country's aerospace industry, the connection technology level used in new aircraft and spacecraft has been continuously improved, and new requirements have been put forward for new fasteners. Ultra-high strength titanium alloy fasteners are one of the future development trends.

 

The application of titanium alloy materials in fasteners has the following advantages:

(1) Low density. The density of titanium alloy is significantly lower than that of steel materials, so titanium alloy fasteners are lighter than steel fasteners.

 

(2) High specific strength. Titanium alloy is a metal material with higher specific strength among common metal materials. Taking advantage of the high specific strength, titanium alloy can also be used to replace lighter aluminum alloy materials. When the external load is the same, the geometric dimensions of titanium alloy parts are smaller, which can effectively save space. This material utilization concept is of great significance to the aerospace field.

 

(3) High melting point. The melting point of titanium alloy is significantly higher than that of steel, so the heat resistance of titanium alloy fasteners is better than that of steel fasteners.

 

(4) Small thermal expansion coefficient and elastic modulus. The thermal expansion coefficient and elastic modulus of titanium alloy are smaller than those of nickel alloy and steel. In the same temperature change range, the thermal stress generated by titanium alloy is very small, so titanium alloy has higher thermal fatigue performance.

 

(5) Non-magnetic. The magnetic permeability of titanium alloy is very small and almost negligible, so titanium alloy fasteners are non-magnetic and can effectively prevent magnetic field interference. Austenitic stainless steel is also non-magnetic, but subsequent cold working will increase its magnetism, while hot or cold working of titanium alloy does not change its magnetism, which makes titanium alloy suitable for use in avionics equipment.

 

(6) High yield strength ratio. The critical strength standard for the design of fasteners subjected to tensile loads is yield strength, followed by tensile strength, because once the fasteners produce yield deformation, they will lose their fastening function. Compared with steel materials, the yield strength of titanium alloy is close to the tensile strength, and the yield strength ratio is higher, so titanium alloy fasteners are safer.

 

(7) The electrode potential matches that of carbon fiber composite materials. The main reason why titanium alloy is used in large quantities in fasteners is that the electrode potential of titanium alloy matches that of carbon fiber composite materials, which effectively prevents the occurrence of galvanic corrosion.

 

(8) In addition, titanium alloy also has the advantages of excellent corrosion resistance and high creep resistance.