Molybdenum, processed by laser powder-bed fusion (LPBF), is susceptible to hot cracking because segregated oxygen impurities significantly weaken grain boundaries through the formation of MoO2. The present study reports on the LPBF processing of the most important molybdenum alloy TZM, whose alloying elements—titanium, zirconium, and carbon—lead to particle and solid solution strengthening. Results of investigations into the resulting microstructure and mechanical properties when processing TZM by LPBF are presented. The alloying elements suppress the segregation of oxygen to the grain boundaries so that crack-free samples with a density of 99.7 ± 0.3% may be produced. The microstructure shows grains that are columnar due to epitaxial grain growth and a weak 〈111〉 fiber texture parallel to the building direction. Mo2C and ZrO2 particles with a size of

Microstructure and mechanical properties of molybdenum-titanium-zirconium-carbon alloy TZM processed via laser powder-bed fusion

A novel crack-free Ti-modified Mo alloy designed for laser powder bed fusion

Molybdenum strip test experiments and simulations at various temperatures to determine friction coefficients

Pseudomonas aeruginosa-accelerated corrosion of Mo-bearing low-alloy steel through molybdenum-mediating chemotaxis and motility

Mechanism of Non-Contact Reduction of MoO3 to Prepare MoO2

Owing to its potential application prospect in novel accident tolerant fuel, molybdenum alloys and their welding technologies have gained great importance in recent years. The challenges of welding molybdenum alloys come from two aspects: one is related to its powder metallurgy manufacturing process, and the other is its inherent characteristics of refractory metal. The welding of powder metallurgy materials has been associated with issues such as porosity, contamination, and inclusions, at levels which tend to degrade the service performances of a welded joint. Refractory metals usually present poor weldability due to embrittlement of the fusion zone as a result of impurities segregation and the grain coarsening in the heat-affected zone. A critical review of the current state of the art of welding Mo alloys components is presented. The advantages and disadvantages of the various methods, i.e., electron-beam welding (EBW), tungsten-arc inert gas (TIG) welding, laser welding (LW), electric resistance welding (ERW), and brazing and friction welding (FW) in joining Mo and Mo alloys, are discussed with a view to imagine future directions. This review suggests that more attention should be paid to high energy density laser welding and the mechanism and technology of welding Mo alloys under hyperbaric environment.

https://www.mdpi.com/2075-4701/10/2/279/pdf

Bu Chunyang

Papers

Research Status and Progress of Welding Technologies for Molybdenum and Molybdenum Alloys