Raw material preparation: High purity is the foundation of alloy properties. Tantalum-tungsten alloys have extremely high requirements for the purity of raw materials (usually Ta purity ≥99.95%, W purity ≥99.9%). Impurities (such as O, N, C, Fe) can seriously reduce the high-temperature strength, plasticity and corrosion resistance of the alloy. Therefore, the core of raw material preparation is "purification" and "morphology transformation".
Tantalum-tungsten alloy is a refractory alloy composed of tantalum (Ta, melting point 3017℃, excellent corrosion resistance) and tungsten (W, melting point 3422℃, extremely high high-temperature strength), combining the advantages of both - it retains the corrosion resistance and processability of tantalum, while significantly enhancing high-temperature strength, hardness and creep resistance through the addition of tungsten. It is mainly used in high-end fields such as aerospace, nuclear industry and electronics. Its production process needs to overcome technical difficulties such as "high melting point, easy oxidation, and difficult control of composition uniformity". The core links can be divided into raw material preparation, alloying, forming processing, and subsequent treatment.
The atomic radii of tantalum and tungsten are similar (Ta: 143pm, W:) (137pm) can form an infinite solid solution, but both have extremely high melting points (both > 3000℃), and it is difficult to achieve uniform alloying through conventional smelting. In industry, the "powder metallurgy method" (mainstream) or "vacuum arc smelting method" is mainly adopted. The former is more suitable for large-scale production, while the latter is suitable for high-end customized products. Key point: After each cold working process, "vacuum annealing" (at a temperature of 800-1200℃, holding for 1-2 hours) must be carried out to eliminate work hardening, restore plasticity, and prevent cracking in subsequent processing.
