What is Titanium
Titanium is an innovative metal characterized by its unique properties and composition. It consists of carbon, nitrogen, hydrogen, oxygen, and minimal impurities, with titanium iodide impurity content kept below 0.1%. Despite its relatively low strength, titanium exhibits exceptional plasticity. In the realm of industrial pure titanium with a purity of 99.5%, it showcases remarkable performance metrics.
Notably, it possesses a density (ρ) of 4.5g/cm³ and a melting point of 1725℃. With a thermal conductivity (λ) of 15.24W/(m·K), it effectively dissipates heat. Its tensile strength (σb) measures 539MPa, while exhibiting an elongation (δ) and area reduction (ψ) of 25% each. The elastic modulus (E) stands at 1.078×105MPa, and the hardness (HB) reaches 195, making it a highly versatile material with wide-ranging applications.
Performance advantages of titanium alloy
(1) Exceptional Strength: Titanium alloys exhibit remarkable strength, with some surpassing the strength of many alloy structural steels. Their specific strength, which considers strength-to-density ratio, outperforms other metal structure materials, enabling the production of lightweight components with high unit strength. Engine components, skeletons, skins, fasteners, and landing gear are among the applications benefiting from titanium alloys' high strength.
(2) High Thermal Strength: Titanium alloys maintain their required strength at significantly higher temperatures compared to aluminum alloys. They can operate in the range of 450-500℃, exhibiting high specific strength within the temperature range of 150℃ to 500℃. In contrast, the strength of aluminum alloys decreases significantly at 150℃. Titanium alloys can withstand temperatures up to 500℃, while aluminum alloys have a limited working temperature below 200℃.
(3) Excellent Corrosion Resistance: Titanium alloys excel in corrosion resistance, particularly in humid atmospheres and seawater environments. They demonstrate superior resistance to pitting corrosion, acid corrosion, and stress corrosion. Additionally, titanium alloys exhibit outstanding corrosion resistance to alkalis, chlorides, chlorine-containing organic substances, nitric acid, and sulfuric acid. However, they have poor resistance to reducing oxygen and chromate media.
(4) Superior Low-Temperature Performance: Titanium alloys retain their mechanical properties at low and ultra-low temperatures. Certain titanium alloys, such as TA7, maintain a certain level of plasticity even at -253℃, making them essential materials for low-temperature applications.
(5) Chemical Reactivity: Titanium possesses high chemical reactivity, readily reacting with elements such as oxygen, nitrogen, hydrogen, carbon monoxide, carbon dioxide, water vapor, and ammonia in the atmosphere. For instance, when the carbon content exceeds 0.2% in titanium alloys, hard titanium carbide (TiC) forms. At higher temperatures, interaction with nitrogen leads to the formation of a hard surface layer of titanium nitride (TiN). Titanium also absorbs oxygen above 600℃, resulting in the formation of a hard layer with high hardness. Increased hydrogen content can lead to embrittlement. Titanium's chemical affinity contributes to surface adhesion phenomena under friction.
(6) Thermal Conductivity and Elastic Modulus: Titanium exhibits relatively low thermal conductivity, measuring about one-fourth that of nickel, one-fifth that of iron, and one-fourteenth that of aluminum. The thermal conductivity of various titanium alloys is approximately 50% lower than that of pure titanium. Additionally, titanium alloys have a smaller elastic modulus, approximately half that of steel. Consequently, their rigidity is comparatively lower, making them prone to deformation. Care should be taken when manufacturing slender rods and thin-walled parts, as titanium alloys exhibit significant spring back during cutting processes, resulting in friction, adhesion, and wear on tool surfaces.
