The Effect of Impurity Elements on the Ductility of Tungsten Alloys

The ductility of tungsten alloy refers to the plastic deformation ability of the alloy material before it ruptures due to stress. It is a combination of mechanical properties with similar concepts of ductility and ductility, and is influenced by many factors, including material composition, raw material ratio, production process, and post-treatment methods. The following mainly introduces the influence of impurity elements on the ductility of tungsten alloys.

The impurity elements in high density tungsten alloys include carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur elements.

Carbon element: Generally speaking, as the carbon content increases, the content of tungsten carbide phase in the alloy also increases, which can improve the hardness and strength of the tungsten alloy, but its ductility will decrease.

Hydrogen element: At high temperatures, tungsten reacts with hydrogen element to form hydrogenated tungsten, which leads to a decrease in the ductility of high density tungsten alloys, and this process also becomes hydrogen embrittlement.

Oxygen element: In general, the presence of oxygen element will reduce the ductility of high density tungsten alloys, mainly because oxygen element will form stable oxides with tungsten, which will generate stress concentration at grain boundaries and within grains.

Nitrogen: The addition of nitrogen can improve the strength and hardness of high specific gravity tungsten alloys, because the formation of solid solution between nitrogen and tungsten atoms will lead to lattice distortion and reinforcement. However, if the nitrogen content is too high, lattice distortion and chemical reactions may lead to an increase in the brittleness of the alloy, thereby reducing its ductility.

Phosphorus: Phosphorus can enter high density tungsten alloys through phosphide impurities in raw materials or pollution during the production process. Its existence can lead to embrittlement of grain boundaries, thereby reducing the ductility of the alloy.

Sulfur element: Sulfur element promotes grain growth, which in turn affects the mechanical properties and ductility of tungsten alloys. In addition, sulfur can also form brittle sulfides at grain boundaries and coarse grains, further reducing the ductility and toughness of the alloy.