Experimental Investigation Of Zr-Al-V Ternary System At 800? Isothermal Section

The development of heat-resistant aluminum material is an important direction of aluminum alloy research.Scandium(Sc)elements as aluminum alloy additive is the most effective.Only trace addition can make aluminum alloy has a very high strengthening effect,corrosion resistance,excellent welding performance and heat resistance.But the scandium is expensive,which lead to application range of scandium aluminum alloy is limited in sports and military.Since the zirconium(Zr)can form a suitable strengthening phase in the aluminum alloy,the solid solubility in the Al matrix is small at the working temperature,and the diffusion coefficient in Al is small,which does not affect the casting ability of the alloy.Therefore,it is highly desirable to replace scandium additives in aluminum alloys.Moreover,vanadium(V)in the aluminum alloy compare with other elements,the diffusion rate is the smallest,which play a role to grain refinement in the casting process,in the formation of aluminum alloy VAl11 and other insoluble compounds.And also it will enhance the recrystallization temperature to refine the recrystallization structure.In order to further understand the mechanism and the relationship between the alloying elements,the phase diagram research is extremely important.In this work,the samples were analyzed by means of equilibrium alloy method combined with scanning electron microscopy and energy dispersive spectrometer(SEM-EDS)and X-ray diffractometer(XRD),also measured the phase relationship of Zr-Al-V ternary compounds at 800 ? isothermal cross section.In this system,a new ternary compound was found,named T phase.It is found that Zr-Al-V system has 15 three-phase regions at 800 ? isothermal section,which is?-Al + Al3 V + Al3 Zr,Al8V5 + Al3 V + Al3 Zr,Al8V5 + T + Al3 Zr,Al3Zr + T + Al2 Zr,Al2Zr + T + ?-V,Al2 Zr + Al3Zr2 + Al3Zr4,Al2 Zr + Al3Zr4 + Al2Zr3,Al2 Zr + Al2Zr3 +AlZr2,Al2 Zr + AlZr2 + AlZr3,Al2 Zr + AlZr3 + ?-Zr,Al2 Zr + V2 Zr + ?-Zr and Al2 Zr +V2Zr + ?-V,Al3Zr2 + AlZr + Al3 Zr,?-Zr + ?-Zr + AlZr3 and T + Al8V5 + V,respectively.Among them,Al3Zr2 + AlZr + Al3 Zr,?-Zr + ?-Zr + Al Zr3 and T + Al8V5+ V three three-phase area is derived from the existing experimental data.Because this experiment did not make experimental points in its corresponding areas.The experimental results show that at 800 ?,T can be in steadily exist with V,Al2 Zr,Al3Zr,Al8V5,which consist of 10.0 ~ 16.5 at.% Zr,52.8 ~ 55.2 at.% Al and 29.3 ~36.3 at.% V.And we can know the maximum solubility of V in Al2 Zr reach to 54.1at.%.