Tantalum-10 tungsten alloy plate. This is a high-performance refractory metal alloy material, representing an important branch of the tantalum alloy family. This alloy plate is designed to address the issue of "insufficient strength" of pure tantalum (especially at high temperatures), while largely retaining the most valuable property of tantalum - its outstanding corrosion resistance. It inherits the top corrosion resistance of pure tantalum to most inorganic acids (including aqua regia, hydrochloric acid, sulfuric acid, and nitric acid) and liquid metals. This is the cornerstone of its application. High strength and creep resistance significantly enhance the strength and creep (slow deformation) resistance from room temperature to ultra-high temperatures while maintaining good plasticity. Although it is more difficult to machine than pure tantalum, it still has good machinability among refractory alloys. It can be formed by methods such as stamping, spinning and stretching. It has excellent solderability and is commonly welded by electron beam welding (EBW) and inert gas shielded welding (GTAW/TIG). High melting point and thermal stability: The melting point exceeds 3000°C, making it suitable for extremely high-temperature environments (especially in oxygen-free conditions).
When severe work hardening occurs during cold forming (such as bending and stretching), frequent intermediate annealing is required to restore plasticity. Annealing must be carried out under high vacuum (better than 10^-5 torr) to prevent oxidation and hydrogen embrittlement. Oxygen, nitrogen, carbon, hydrogen and other impurities in the gap can seriously damage its plasticity. It is essential to strictly prevent contamination during high-temperature processing and heat treatment. The problem of high-temperature oxidation (the same as all tantalum materials) begins to oxidize rapidly when the temperature in the air exceeds 300°C. When used in an oxidizing atmosphere, protective coatings (such as silicide coatings, precious metal coatings) must be relied upon. The costs of raw materials (Ta, W) and production processing (vacuum melting, vacuum annealing, precision forming) are extremely high.
While retaining the corrosion resistance and high melting point of tantalum crown grade, it has achieved high strength sufficient to withstand mechanical stress, especially high-temperature strength, by adding tungsten. It is applied to those critical structural components where the corrosive environment is so extreme (tantalum is indispensable), and the temperature, pressure or mechanical load is so high that pure tantalum cannot meet the requirements. Not only is the material itself expensive, but its strict processing, welding and heat treatment requirements (requiring high vacuum or high-purity protection throughout the process) also greatly increase the manufacturing cost.
Compared with pure tantalum, the high-temperature tensile strength of Ta-10W alloy is increased by 40% to 60%, and its creep resistance at 1200℃ (1000h fracture stress) is more than three times that of pure tantalum. It can be used for a long time below 1400℃, and the short-term service temperature can reach 1800℃ (under inert atmosphere protection). Inheriting the corrosion resistance of pure tantalum, it can resist the vast majority of organic/inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and aqua regia (including concentrated acid environments below 200℃), except for hydrofluoric acid, hot concentrated phosphoric acid, molten alkali and fluorine-containing compounds. Its corrosion resistance is superior to that of commonly used corrosion-resistant materials such as Hastelloy and titanium alloys. At room temperature, plastic processing such as rolling, bending, stamping and welding can be carried out. Through multiple passes of rolling and intermediate annealing, plates with a thickness ranging from 0.1mm to 50mm can be made. Welding can be carried out by tungsten inert gas welding (TIG) or electron beam welding (EBW), and the strength of the welded joint can reach 85% to 95% of the base material. It has an extremely low vapor pressure at high temperatures (vapor pressure ≈1.2×10-4Pa at 1600℃) and is not volatile in a vacuum environment. After adding 10% W, its antioxidant brittleness resistance is superior to that of pure tantalum. It is not prone to brittleness when exposed to air for a short period of time (< 600℃). For long-term high-temperature use, it needs to be combined with antioxidant coatings such as SiC and Al2O2. The oxide scale is removed by acid washing (a mixture of hydrofluoric acid and nitric acid), and then electrolytic polishing is carried out to make the surface roughness Ra≤0.8μm, meeting the usage requirements of precision components.
