Investigation On Mechanical Property And Oxidation Resistance Property Of Mo-12Si-8.5B Alloy Prepared By Liquid—Liquid Method

Due to the Mo-12Si-8.5B alloy can improve performance by doping rare earth oxides,rare earth oxide doped Mo-12Si-8.5B alloy has great potential to become a new generation of high temperature structural materials.The most commonly used method for doping rare earth oxide in industry is solid-solid doping method.However,it is difficult for solid-solid doping method to control the dimension scale and the distribution of the rare earth oxide particles.As a result,the mechanical behavior of the Mo-12Si-8.5B alloy can hardly be enhanced.Newly developed liquid-liquid doping method can keep the dimension scale and the distribution of the rare earth oxide particles in good control,thus is a most promising method for preparation of.Mo-12Si-8.5B alloy with high strength and toughness.Mo-12Si-8.5B alloys doped with different mass fraction(0.3 wt.%,0.6 wt.%,0.9 wt.%)lanthanum oxide(La2O3)was prepared by liquid-liquid(L-L)doping,mechanical alloying and hot pressing sintering techniques.Studied alloy microstructure,mechanical properties and oxidation resistance,discussed the influence of the doping amount on alloy microstructure and mechanical properties and oxidation resistance.The microstructure,mechanical properties and oxidation resistance of Mo-12Si-8.5B alloy made by liquid-liquid doping method and solid-solid doping method were compared and discussed.The observation of microstructures of the Mo-Si-B alloys shows the alloys grain size were refined with the increasing of La2O3 doped.The compressive strength of alloy is obviously enhanced with ascension of lanthanum oxide content.As showed by the results of comparison,the dimension of the dislocation cells in the alloy prepared by liquid-liquid doping method is smaller than that alloy prepared by solid-solid doping method.Fracture toughness values of the alloys are over 10MPa·m1/2 that reveal the addition of La2O3 by L-L doping method can obviously improve the alloy fracture toughness than the alloys doping La2O3 by solid-solid(S-S)doping method.The compression tests show that the compression strength of the alloys was improved than Mo-12Si-8.5B alloys.In addition,the oxide resistance of the alloy prepared by liquid-liquid doping method is better than alloy prepared by solid-solid doping method.