Tungsten And Molybdenum Materials, Rare Earth Phase Morphology And Evolution,

In this paper, several advanced analytical instruments have been used to study the existent pattern of the rare earth phases in the Tungsten and Molybdenum products. There are many results which can guide the production and scientific research.In tungesten and Molybdenum material ,rare earth elements don't react with the matrix but form the oxides. When several rare earth elements or rare earth with Titanmium,Zirconium were doped together ,they form composite oxides.In the ingots the particles of rare earth oxide are dispersive distribution. Therefore,the strenthening mechanism of rare earth is dispersive atrenthening. The particles exist not only on the boundaries but also in the grains. The particles on the boundaries ,which are bigger than that in the grains, have varied shape, such as spheroidal, chain and drop,when the category of rare earth or the sintering technology are changed.During the pressure process the shape of the rare earth particles changed obviously. Usually,they are stretched step by step and form the fibers fmally,but the Y2O3 particles can't form the fibers and just smash.During the heating process the fibers of rare earth oxide break and become the spheral particles progressively. These particles don't migrate and grow up obviously even at the higher temperature.