Titanium alloy(2)
Date:2012-10-15 09:35 Source:未知 Author:admin Click:
- Grade 6 contains 5% aluminium and 2.5% tin. It is also known as Ti-5Al-2.5Sn. This alloy is used in airframes and jet engines due to its good weldability, stability and strength at elevated temperatures.[citation needed]
- Grade 7 contains 0.12 to 0.25% palladium. This grade is similar to Grade 2. The small quantity of palladium added gives it enhanced crevice corrosion resistance at low temperatures and high pH.
- Grade 7H is identical to Grade 7 with enhanced corrosion resistance.
- Grade 9 contains 3.0% aluminium and 2.5% vanadium. This grade is a compromise between the ease of welding and manufacturing of the "pure" grades and the high strength of Grade 5. It is commonly used in aircraft tubing for hydraulics and in athletic equipment.
- Grade 11 contains 0.12 to 0.25% palladium. This grade has enhanced corrosion resistance.
- Grade 12 contains 0.3% molybdenum and 0.8% nickel.
- Grades 13, 14, and 15 all contain 0.5% nickel and 0.05% ruthenium.
- Grade 16 contains 0.04 to 0.08% palladium. This grade has enhanced corrosion resistance.
- Grade 16H contains 0.04 to 0.08% palladium.
- Grade 17 contains 0.04 to 0.08% palladium. This grade has enhanced corrosion resistance.[citation needed]
- Grade 18 contains 3% aluminium, 2.5% vanadium and 0.04 to 0.08% palladium. This grade is identical to Grade 9 in terms of mechanical characteristics. The added palladium gives it increased corrosion resistance.[citation needed]
- Grade 19 contains 3% aluminium, 8% vanadium, 6% chromium, 4% zirconium, and 4% molybdenum.
- Grade 20 contains 3% aluminium, 8% vanadium, 6% chromium, 4% zirconium, 4% molybdenum and 0.04% to 0.08% palladium.
- Grade 21 contains 15% molybdenum, 3% aluminium, 2.7% niobium, and 0.25% silicon.
- Grade 23 contains 6% aluminium, 4% vanadium, 0.13% (maximum) Oxygen. Improved ductility and fracture toughness with some reduction in strength.
- Grade 24 contains 6% aluminium, 4% vanadium and 0.04% to 0.08% palladium.
- Grade 25 contains 6% aluminium, 4% vanadium and 0.3% to 0.8% nickel and 0.04% to 0.08% palladium.
- Grades 26, 26H, and 27 all contain 0.08 to 0.14% ruthenium.
- Grade 28 contains 3% aluminium, 2.5% vanadium and 0.08 to 0.14% ruthenium.
- Grade 29 contains 6% aluminium, 4% vanadium and 0.08 to 0.14% ruthenium.
- Grades 30 and 31 contain 0.3% cobalt and 0.05% palladium.
- Grade 32 contains 5% aluminium, 1% tin, 1% zirconium, 1% vanadium, and 0.8% molybdenum.
- Grades 33 and 34 contain 0.4% nickel, 0.015% palladium, 0.025% ruthenium, and 0.15% chromium .[citation needed]
- Grade 35 contains 4.5% aluminium, 2% molybdenum, 1.6% vanadium, 0.5% iron, and 0.3% silicon.
- Grade 36 contains 45% niobium.
- Grade 37 contains 1.5% aluminium.
- Grade 38 contains 4% aluminium, 2.5% vanadium, and 1.5% iron. This grade was developed in the 1990s for use as an armor plating. The iron reduces the amount of Vanadium needed as a beta stabilizer. Its mechanical properties are very similar to Grade 5, but has good cold workability similar to grade 9.
Titanium alloys used biomedically
- Ti-6Al-4V is cytotoxic due to its vanadium content. While having excellent biocompatibility, Ti-6Al-4V also suffers from poor shear strength and poor surface wear properties:
"Biocompatibility: Excellent, especially when direct contact with tissue or bone is required. Ti-6Al-4V's poor shear strength makes it undesirable for bone screws or plates. It also has poor surface wear properties and tends to seize when in sliding contact with itself and other metals. Surface treatments such as nitriding and oxidizing can improve the surface wear properties.
- Ti-6Al-7Nb was developed as a biomedical replacement for Ti-6Al-4V alloy because Ti-6Al-4V contains cytotoxic vanadium. Ti-6Al-7Nb contains 6% aluminium and 7% niobium.
"Ti6Al7Nb is a dedicated high strength titanium alloy with excellent biocompatibility for surgical implants. Used for replacement hip joints, it has been in clinical use since early 1986.
