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

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

The invention provides a method for preparing a small-sized high-accuracy molybdenum alloy part. The method comprises the following steps: 1, performing ball milling on molybdenum powder and additive powder to obtain composite molybdenum alloy powder, then adding the composite molybdenum alloy powder and a solution into a circulating slurry tank to prepare suspended slurry, performing spray granulation treatment to obtain spherical granulated powder, and performing screening; 2, performing continuous compression molding to obtain a compact; 3, performing pre-sintering; 4, performing sintering; 5, performing hot isostatic pressing sintering; 6, performing finishing to obtain the small-sized high-accuracy molybdenum alloy part. The molybdenum alloy part prepared by the method is uniform in component distribution and high in size accuracy, and machining can be avoided or reduced.

Method for preparing small-sized high-accuracy molybdenum alloy part

The utility model discloses a crucible forming die, including the bed die, the mandrel, go up the formpiston, lower formpiston, pressure pad and die crushion, the die crushion include interior die crushion and cover establish including the outer outer die crushion of die crushion, including the mandrel sets up on the die crushion, formpiston and pressure pad all set up and stack up at the external mold down, the lower part at the mandrel is established to the xiayang die sleeve, the pressure pad cover is established under outside the formpiston and is left the clearance down between the formpiston, the bed die sets up on the pressure pad, the formpiston lies in between bed die and the mandrel down, lower formpiston and bed die and the equal sliding fit of mandrel, the lower part of going up the formpiston lies in the bed die, go up the lower part and bed die sliding fit of formpiston, go up the formpiston, lower formpiston, the mandrel becomes the die cavity with the cavity that the bed die formed for the crucible, the lower part center of mandrel is provided with drawing of patterns hole. The utility model has the advantages of being simple in structure and convenient in operation, simple, the repeatedly usable of production processes utilizes accurate, of high quality, the long service life of this mould institute system crucible size, has effectively reduced the machining volume, has improved utilization ratio of material.

Crucible forming die

The invention discloses a method for preparing a molybdenum disulfide sputtering target material. The method comprises the following steps that firstly, a molybdenum disulfide raw material powder is subject to low-pressure pressing treatment, and a molybdenum disulfide blank is obtained; the molybdenum disulfide blank is subject to ball milling under inert gas protection, and molybdenum disulfidepowder is obtained; thirdly, the molybdenum disulfide powder is loaded into a rubber sleeve to be subject to cold isostatic pressing treatment, and a molybdenum disulfide forming blank is obtained; fourthly, the molybdenum disulfide forming blank is loaded into a package sleeve, after vacuum pumping and welding, hot isostatic pressing sintering treatment is carried out, the package sleeve is removed, and a molybdenum disulfide target material crude product is obtained; fifthly, the molybdenum disulfide target material crude product is subject to mechanical machining and cleaning, and the molybdenum disulfide sputtering target material is obtained. The low-pressure pressing and ball milling process is adopted, the molybdenum disulfide powder is converted to be of a similarly-spherical particular structure from an irregular sheet-shaped structure, powder pressing is improved, combination force between powder is enhanced, and the quality of the molybdenum disulfide sputtering target material is improved.

Method for preparing molybdenum disulfide sputtering target material

The utility model discloses a crucible isostatic compaction mould, including elastic die and rigidity mould, elastic die includes packing element, rubber cover plate and offset plate, the rigidity mould includes end cover, mandrel and solid fixed cylinder, form the powder forming chamber between mandrel, packing element and the offset plate, gu be provided with first filling hole on the fixed cylinder, be provided with the second filling hole on the end cover, the inside of mandrel is provided with the mandrel hole, the mandrel sets up. The utility model discloses simple structure, reasonable in design, it is accurate reliable, set up elastic die and rigidity mould, the rigidity mould has guaranteed that the inside dimension in powder forming chamber is accurate, and elastic die evenly suppresses and guarantees pressed compact density distribution evenly just the uniformity is good, and the mandrel does not have spends slightly, has both reduced reservation processing volume, has improved the utilization ratio of raw and other materials, has reduced machining's work load again, makes efficiently, and the practicality is strong.

Wang Na

Papers

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

Method for preparing small-sized high-accuracy molybdenum alloy part

Crucible forming die

Method for preparing molybdenum disulfide sputtering target material

Crucible isostatic compaction mould