In the field of industrial materials, the two important metal substrates, pure titanium sheet and composite titanium sheet, have significant differences in the element composition, the physical properties and the engineering applications. In this paper, the characteristics of these two types of titanium-based materials and their application scenarios will be deeply analyzed from the perspective of material science.
Comparison of material composition and microstructure
-
Pure titanium sheet(Grade 1-4)
Manufactured by industrial pure titanium, titanium content ≥99.0%, according to ASTM standards, it divided into four grades. Its crystal structure is mainly close-packed hexagonal (α phase) structure, with anisotropic characteristics. The typical impurity elements include oxygen, iron, carbon and nitrogen, among which oxygen content has significant influence on the material strength.
-
Composite titanium sheet
It is produced by multi-component alloying process, which is mainly divided into α+β biphase alloy (such as Ti-6Al-4V) and β phase alloy (such as Ti-15V-3Cr-3Sn-3Al). The content of alloy elements is usually between 5-15%. The solid solution strengthening and phase transformation strengthening are achieved by adding Al, V, Mo, Nb and other elements.
Comparison of mechanical properties parameters
Through the analysis of experimental data, the key performance indexes of the two kinds of materials are significantly different.
|
Performance indexes |
Pure titanium sheet |
Ti-6Al-4VComposite titanium sheet |
|
Strength of extension(MPa) |
240-550 |
895-930 |
|
Yield strength(MPa) |
170-485 |
825-869 |
|
Elongation (%) |
15-24 |
10-15 |
|
Elasticity modulus(GPa) |
102-110 |
110-114 |
|
Fatigue strength(MPa |
200-300 |
500-600 |
|
Breaking tenacity(MPa√m) |
40-60 |
50-80 |
Analysis of engineering application scenarios
Typical applications of pure titanium sheet
- Chemical equipment: Chlor-alkali industrial electrolytic cell liner (annual corrosion rate < 0.05mm)
- Marine engineering: Seawater desalination plant tube plate (service life > 20 years)
- Medical implants: Orthopedic fixation plates (ISO 5832-2 biocompatibility certified)
- Construction field: Waterfront building curtain wall system (salt spray test > 5000h)
Applications of composite titanium sheet
- Aerospace: Engine compressor blades (operating temperature 450-500℃)
- Medical equipment: Bearing parts of artificial joints (wear rate < 0.1mm³/Mc)
- Sports equipment: Race-grade bicycle frames (specific strength up to 300kN·m/kg)
- Military equipment: Submarine pressure shells (submersible depth ≥500m)
Surface treatment process differences
The pure titanium sheets are mostly anodized (voltage 80-100V) to form 5-20μm oxide film, and the surface hardness can reach to HV800. The composite titanium sheet needs to be strengthened by shot blasting (shot diameter 0.3-0.6mm), and the surface residual compressive stress can reach -800MPa, which significantly improves the fatigue resistance.
Welding processing characteristics
The welding of pure titanium sheets should be strictly controlled in the environment of 99.999% argon purity , and the width of the heat affected zone is about 3-5mm. The composite titanium sheets should be welded by the electron beam. The vacuum degree is < 5×10⁻³Pa, the welding speed is 15-30mm/s, and the stress relief annealing should be carried out at 550℃/4h after welding.
Cost-benefit analysis
Current market data shows that the raw material cost of the composite titanium sheets is about 2-3 times higher than that of the pure titanium sheets, but because of its strength advantages, the material consumption can be reduced by 30-40% under the same load-bearing conditions. The life cycle cost analysis shows that the use of composite titanium sheets in high-end equipment fields has better economy.
With the development of material preparation technology, new titanium alloy materials such as Ti-5553 (Ti-5Al-5Mo-5V-3Cr) have achieved a strength breakthrough of 1200MPa, and the corrosion resistance of nanocrystalline pure titanium has increased more than 50% compared with traditional materials. The material engineers need to choose a better optimal solution based on the requirements of the specific working conditions and the comprehensive balance between corrosion resistance, strength and cost.