Molybdenum-rare earth oxide alloy (Mo-REO), also called rare earth molybdenum, is an alloy of molybdenum and rare earth element oxides, which is an oxide dispersion-strengthened alloy, similar to rare earth tungsten. Commonly used rare earth element oxides are Y2O3, La2O3, CeO2, and Nd2O3, Sm2O3, Gd2O3, and Sc2O3. They are usually added in the alloy in an amount of 0.5% -3.0% (mass fraction).
The rare earth oxide doped molybdenum is a new material that has been systematically researched since the late 1980s. The addition of rare earth oxides can not only significantly increase the strength of molybdenum, improve the high temperature resistance of molybdenum, but also significantly increase the recrystallization temperature of molybdenum and reduce the brittleness of molybdenum restructure. It is an excellent high temperature structural material. The overall performance is better than the high-temperature molybdenum (Mo-ASK) and TZM molybdenum alloy originally considered to be the best. Rare earth oxide-doped molybdenum is also a new type of electronic functional material-thermionic emission cathode material. Its emission capacity reaches or exceeds the current W-ThO2 materials, which overcomes the radioactive contamination and brittle fracture problems of W-ThO2 materials. As a result, the working temperature of the electric vacuum device is reduced by 150 to 200 ° C. Therefore, rare earth molybdenum as a new type of electronic functional material is attracting increasing attention from material experts and electron tube experts.
In recent years, research on rare earth molybdenum, on the one hand, research on the strengthening mechanism and electron emission mechanism of rare earth oxides on molybdenum, and to clarify the strengthening, toughening and electron emission mechanisms of rare earth oxides, some progress has been made; On the one hand, the research and development of the application of rare earth molybdenum are systematically carried out. For example, Austria’s Plansee has successfully developed Mo-Y2O3 foil for special lamps.
The molybdenum-rare earth oxide alloys are classified as follows:
Dispersion strengthened alloy
Unit system: Mo-La2O3, Mo-Y2O3, etc.
Multivariate: Mo-La2O3-Y2O3, Mo-Y2O3-Sc2O3
Precipitation strengthening + dispersion strengthening alloy:
TZM-La2O3, TZM-CeO2, TZM-Y2O3
TZC-CeO2, TZC-La2O3, TZC-Y2O3, TZC-CeO2-Y2O3
ZHM-Y2O3, ZHM-La2O3, ZHM-CeO2
At present, the most important molybdenum-rare-earth oxide alloy is Mo-La2O3, which systematically studies the fracture initiation, high-temperature strength, ductile transition temperature (DBTT), and the properties of the foil. Developed Mo-La2O3 (0.3-1.0%) high temperature resistant molybdenum, which is widely used in high temperature furnaces. This alloy has a higher use temperature than pure molybdenum and higher processability than TZM Molybdenum.