Activated Recrystallization of Non-Sag Tungsten Wire(2)

Under a low temperature condition, the recrystallization will occur by adding some metals to the wire surface which is an important process when the wires act as reinforcement material in metal matrix composites because of its damage to the mechanical properties of non-sag tungsten wires.

The activated recrystallization was studied both for nickel plated and palladium plated 0.18 mm cold drawn doped tungsten wire. A recrystallized structure formed in both types of wires after annealing at 1100°C for 100 hours, but their structural features were different. Palladium presence will lead to recrystallizing behavior, which was very similar to that of un-doped tungsten wire, whereas the behavior of nickel plated wire was similar to the general recrystallization of doped wire, except for the much lower recrystallization temperature. This indicated that palladium was more effective as an activator than nickel was.

It was shown, using Atom Probe Field Ion Microscopy (APFIM) analysis, whose grain boundaries and lattice dislocations could act as fast paths for diffusion of activators in tungsten wire during annealing. The presence of the large potassium bubbles and the segregation of activators on potassium bubbles indicated that the effect of activators was to neutralize the impeding influence of potassium bubbles on dislocation movement and boundary migration.

Two types of nickel rich precipitates were found. One was a Ni (W) solid solution, which formed on the bubbles at grain boundaries, and another type, with Ni4W structure, was found on the potassium bubbles connected with dislocations. Palladium rich precipitates were present only in triple junctions. Their structure could not be established.

 

Tungsten Metals Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten.com.cn
 Tel.: 86 592 5129696; Fax: 86 592 5129797
 Email: sales@chinatungsten.com
 Tungsten & Molybdenum Information Bank: http://i.chinatungsten.com
 Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
 Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn

• < 前へ
• 次へ >