MICROSTRUCTURES AND PROPERTIES OFMOLYBDENUM WIRES DOPED WITH La
(1.Department of Materials Science and Engineering; Beijing Polytechnic University; Beijing 100022
2.Universiyt of Science and Technology Beijing; Beijing 100083
3.Central South University of Technology; Changsha 410083)
2.Universiyt of Science and Technology Beijing; Beijing 100083
3.Central South University of Technology; Changsha 410083)
Abstract: The structures and properties of the La-doped molybdenum(La-Mo) powder , compact , rods and wires annealed at different temperatures were investigated. The experimental results show that the to exists in the powders in the forms of lanthanum nitrate , lanthana and complex oxides of molylxlenum and lanthanum , whereas the bo exsists in the compacts, reds and annealed wiresin the form of lanthana. Upon annealing at 1600 ℃ , the elongated La2O3 in wires breaks up intorows of La2O3 particles. The recrystallization temperature of molybdenum wires has been in-creased , and its ductility and the creepresistunt properties have also been improved by addition of lower-content of La2O3. Morever , grain structure with large aspect ratio has been formed in theMo wires doped with lower content of La2O3. When the La2O3 reaches higher content , the La-Mowires show excellent thermionic electron properties and less recrystallised low-temperature embrittlement.
Key words: molytxlenum La microstructure recrystallization strengthening toughening