Analysis of Titanium Alloy Characteristics

Titanium and titanium alloys have good corrosion resistance and are typical corrosion-resistant metals. In the atmosphere and ocean, titanium alloys can resist corrosive media such as acids, alkali and salt spray, and their corrosion resistance is second only to aluminum and stainless steel.

However, in water, titanium will react with oxides such as chlorine, oxygen, sulfur and nitrogen to cause corrosion. The corrosion resistance of titanium in seawater is worse than that of stainless steel, and hydrogen embrittlement may form in seawater.
Titanium and titanium alloys have high elastic modulus, good plasticity and processability. This is because they have excellent comprehensive properties such as high specific strength, low density, good fatigue resistance, small linear expansion coefficient, high temperature and low temperature resistance, etc. performance.
Titanium alloys have good plasticity and toughness at room temperature. During hot processing, when the temperature does not exceed 450°C, titanium alloys can still maintain high plasticity, even at high temperatures.
Therefore, titanium alloys can be widely used in the aerospace field. Titanium alloy also has high strength, its strength is 1.5~2.5 times that of steel, and its strength is about 50% higher than steel; when an appropriate amount of rare earth elements are added to the alloy, its strength can be more than doubled; when titanium alloy is added With an appropriate amount of magnesium, its strength can be increased by 2 to 4 times.
Titanium and titanium alloys have a large specific heat (about 10 times that of steel). This is due to the low density of titanium alloys due to their high specific heat. When titanium alloy is heated to a certain temperature, it will absorb a large amount of heat, and a phase change reaction will occur at high temperature, causing its volume to expand. This volume expansion will cause its specific heat to increase significantly. The density is about 1/3 of steel, 1/2~1/4 of aluminum and stainless steel; the elastic modulus is about 1.5 times of steel and 2~3 times of stainless steel, and titanium alloy is 2~3 times of steel and aluminum. ;At the same time, its hardness is also low (about as hard as steel and aluminum or stainless steel). Therefore, it is very suitable for manufacturing aircraft engine blades, rocket thruster casings, etc.

Titanium and titanium alloys have excellent thermal insulation properties, and their thermal conductivity is only 1/3~1/4 of the thermal conductivity of metals in materials such as copper and aluminum. At the same time, it also has excellent heat dissipation performance, good air permeability and thermal conductivity, and can quickly dissipate heat to the surrounding environment. Titanium alloys only absorb about 20% of heat under normal circumstances, but can absorb about 40% of heat at high temperatures. Therefore, under high temperature conditions, titanium alloys can withstand higher temperatures for a long time without being oxidized; they can still maintain good properties even above 300°C. Therefore, titanium and titanium alloys are often used to manufacture high-temperature, corrosion-resistant or high-temperature-resistant structural parts.
Due to its good corrosion resistance and mechanical properties, it can be used as a material instead of steel and aluminum in many occasions. However, if it can be combined with other metal materials and appropriate heat treatment processes, its corrosion resistance can be further improved.
Its plastic deformation ability is low at room temperature; but its deformation ability at low temperatures is similar to that of aluminum alloys, and its work hardening rate is also low. Therefore, titanium and titanium alloys are suitable for manufacturing structural parts and machine parts.
It has good weldability at normal temperature; it can be welded at high temperatures; it can be welded into various parts and connectors with complex shapes and high dimensional accuracy requirements; it can be welded by flame or arc welding methods.
Welding can be carried out by argon arc welding, resistance welding and electric brazing methods. At the same time, titanium and titanium alloys can be welded and brazed with a variety of metal materials, so they can be used to obtain components with larger thicknesses, complex shapes, or high dimensional accuracy requirements but low strength. The elastic modulus is a measure of metal An important indicator of the material's ability to resist deformation and its performance.