The Study On Glass Forming Ability And Mechanical Propertity Of W-Fe Based Alloys

In this paper,the glass forming ability(GFA) of the W-based alloys is investigated by means of research a series of W-Fe-B and W-Fe-C-B alloys.Mother alloys with different composition were prepared by using arc melting facility.Ribbons with thickness of 45μm were fabricated by single roller melt spun method and rods with a diameter of 3mm were made by copper mold casting method.The melting behavior,the microstructure,the glass formation and the phase constituent were checked by using different temperature analysis (DTA),scanning electronic microscopy(SEM),respectively.The results show that W-Fe-B ternary alloys are not fully amorphous structure,adding C element decrease the melting point and increase the GFA of the alloy.The ratios of C and B is between 0.28 and 0.88,the W₃₀Fe₃₈C_xB_32-x alloys exhibit good GFA when C and B is 32at.%.The fully amorphous structure was observed at the ratio of 0.45 for W₃₀Fe₃₈C₁₀B₂₂.The DSC results indicate that the amorphous ribbons exhibit apparent crystalline temperature above 980K.A two-step crystallization behavior was observed for the amorphous ribbons.It is a highlight to find that When increase the content of W in W-Fe-C-B alloys,the ratio of C and B that requires glass formation will increase,and an amorphous ribbon with composition of W₃₅Fe₃₀C₁₅B₂₀ was found when the ratio is 0.75.It is a highlight to find that a three-step crystallization behavior was observed for the amorphous ribbon with an onset crystalline temperature 997K.By adding 2at.%Er to replace Fe in W₃₀Fe₃₈C₁₅B₁₇ alloy,amorphous ribbons were successfully prepared by single roller melt spun method.The morphology of as-cast alloys with 3mm in diameter show that the microstructure of as-cast alloy with Er element exhibits fine and evenly distributed structure.Uniaxial compressive tests of the as-cast rods reveal that adding Er in W₃₀Fe₃₈C₁₅B₁₇ the mechanical properties of Er-containing alloy are much improved.The facture strength and fracture strain increase from 2749MPa and 5.5% for W₃₀Fe₃₈C₁₅B₁₇ alloy to 3012MPa and 8.2%for W₃₀Fe₃₆C₁₅B₁₇Er₂,respectively.