The Research On The Preparation And Properties Of TZM-La₂O₃ Alloy Plate

TZM alloys (Titanium-Zirconium-Molybdenum Alloys) have been applied in manyfields with high melting point, high corrosion resistance, excellent mechanicalproperties, and many other advantages. With the development of modern industry andtechnology, more higher requirements of TZM alloy are come up. It can significantlyincrease the recrystallization temperature and the plasticity and toughness of TZM alloyto add rare earth oxide to molybdenum, and the rare earth molybdenum alloy with lessthan 1.0% La₂O₃ (mass percent) has been widely concerned.In this thesis, The author used Mo powder, TiH₂ powder, ZrH₂ powder, rare earthoxides La₂O₃ and graphite powder as raw materials to prepare TZM-La₂O₃ alloy slab byPowder Metallurgy, then 0.5mm TZM-La₂O₃ plate was prepared by rolling. The authorstudied the effects of La₂O₃ on the microstructure and properties of TZM alloy plate,and compared the differences of the microstructure and properties of TZM-La₂O₃ alloyplate between the one-way rolling and the cross rolling. The main results are as follows:It can significantly refine the grain of TZM alloy slab to add La₂O₃, and therefinement effect was more obvious with the increasing of La₂O₃ content (mass percent)(from 25μm down to 15μm). La₂O₃ particles dispersion filled the holes in the sintering,which increased the density of the sintered TZM alloy slab( the relative density is over97.5%), and the hardness of the slab raised with the increasing of La₂O₃content(Rockwell hardness (HRC) increased from 65 to 77).It significantly delayedrecrystallization to add La₂O₃, and TZM alloy recrystallization temperature wasgradually increased with the increasing of La₂O₃ content. TZM-0.1La₂O₃ alloy platerecrystallization temperature was 1300℃(increased by about 100℃); TZM-0.6La₂O₃ alloy plate recrystallization temperature was 1500℃(increased by about 300 ).℃La₂O₃particles had a significant toughening effect on TZM alloy plate, and it can significantlyincrease the tensile strength and elongation of TZM alloy plate at room temperature.One-way rolling TZM-La₂O₃ alloy plate had higher recrystallization temperature andtensile strength than the cross rolling TZM-La₂O₃ alloy plate alloy plate, but itselongation was lower. One-way rolling TZM-La₂O₃ alloy plate had obvious anisotropy,but the cross rolling can change the metal flowing direction, which can significantlyremove the anisotropy of molybdenum plate microstructure to make TZM-La₂O₃ alloyplate alloy plate get more uniform performance.