3D Printing Technology For The Production Of Molybdenum Alloys

As a typical representative of refractory materials, tungsten-molybdenum alloys can be produced using laser additive manufacturing technology in addition to electron beam deposition processes. However, both the laser process and the electron beam process are 3D printing technologies.

Electron beam additive manufacturing technologies generally include both electron beam selective melting and electron beam filament deposition forming technologies. Compared to laser additive manufacturing techniques, electron beam additive manufacturing has more potential to manufacture tungsten-molybdenum alloys using electron beam additive because of the higher thermal energy and the higher temperature of the melt pool formed by scanning, in addition to the higher absorption of electron beam energy by the material.

The electron beam filament deposition process is characterized by high energy input, high deposition efficiency, and good vacuum cleanliness and can be used for the direct preparation of complex parts, thus providing a good solution to the shortcomings of existing production techniques for molybdenum alloys.

Studies have shown that there is a direct link between the grain growth inside the deposited layer and the parameters of the electron beam filament deposition process, with beam density having the greatest influence on grain growth. The molybdenum alloy deposited using the electron beam deposition process has no obvious dispersion enhancing particles inside the deposited layer, the alloying elements are mainly in solid solution form, while the titanium burn-off is very serious, and the titanium added to the wire material does not play a good solid solution enhancing effect.

In the electron beam process, the thickness of the powder layer can reach 75-200 μm, and in the additive manufacturing process, it can ensure good interlayer bonding quality, and the powder particle size requirement is low, which greatly reduces the cost of powder consumables. Molybdenum + titanium carbide metal-based composite powders have been prepared using mechanical alloying methods and fused with pure molybdenum powder in an electron beam powder bed to form sandwich structures for additive manufacturing. The molybdenum + titanium carbide solid layer forms a hybrid structure of molybdenum with discrete titanium carbide particles, eutectic molybdenum + titanium carbide, and molybdenum dendrites. Thermodynamic simulations show that the system contains constant eutectic reactions within the composition range used and indicate that the system is highly sensitive to changes in composition and temperature.