Molybdenum alloy is a non-ferrous alloy composed of molybdenum as the matrix and adding other elements. The main alloying elements are titanium, zirconium, hafnium, tungsten and rare earth elements. Titanium, zirconium and hafnium elements not only play a solid solution strengthening role in molybdenum alloy and maintain the low-temperature plasticity of the alloy, but also form a stable and diffusely distributed carbide phase to improve the strength and recrystallization temperature of the alloy. Molybdenum alloy has good thermal conductivity, electrical conductivity and low expansion coefficient, and has high strength at high temperature (1100~1650°C), which is easier to process than tungsten. It can be used as a gate and anode for electron tubes, a support material for electric light sources, and for making die-casting and extrusion molds, spacecraft parts, etc. Because molybdenum alloys are brittle at low temperatures and brittle in welding, and easy to oxidize at high temperatures, their development is limited. The industrially produced molybdenum alloys include molybdenum-titanium-zirconium, molybdenum-tungsten and molybdenum rare earth alloys, and the first type is more widely used. The main strengthening methods of molybdenum alloys are solution strengthening, precipitation strengthening and work hardening. Molybdenum alloy plates, strips, foils, tubes, bars, wires and profiles can be prepared through plastic processing, and their strength and low-temperature plasticity can also be improved.
Among refractory metals, molybdenum and its alloys have good thermal conductivity, electrical conductivity and low coefficient of expansion (similar to glass used for tubes), high strength at high temperatures (1100~1650 °C), and are easy to process compared with tungsten, so they are used in the manufacturing sector of electron tubes (gate and anode), electric light source (support material), metal processing tools (die-casting and extrusion dies and perforated heads) and the aerospace industry. Molybdenum is resistant to the erosion of molten glass, and its oxides do not contaminate the glass. Since 1943, molybdenum has been used in the glass industry as a heating electrode. Mo-30W alloy has excellent resistance to molten zinc corrosion and has been successfully applied to the zinc smelting industry. Molybdenum is also used in the manufacture of components such as heat exchangers and valves in the production of sulfuric acid.