Effect Of Composition Change Of Ti And Zr On Microstructure And Mechanical Properties Of TiZrAlFe Alloy

Titanium and titanium alloys have been widely used in aerospace industry,marine vessels,biological materials,chemical industry and other fields due to low density,high specific strength,good corrosion resistance and excellent processing performance.But the strength of titanium alloys is obviously lower than that of iron and steel material,which limits extensive application of Ti alloys.In order to overcome this shortcoming,it is necessary to enhance the strength of titanium alloys.In this paper,the Ti-6Al-4Fe is selected as the matrix and Zr as the alloying element is used to replace Ti content of the Ti-6Al-4Fe alloy.A series of new TiZrAlFe alloys were designed and prepared by non-consumable electro-arc furnace.DSC,XRD,OM,SEM and tensile test were employed to investigate the microstructure and mechanical properties of these alloys,in which the compositions are Ti-6Al-4Fe 、 Ti-5Zr-6Al-4Fe 、 Ti-10Zr-6Al-4Fe 、Ti-15Zr-6Al-4Fe、Ti-20Zr-6Al-4Fe.Investigation of the microstructure and mechanical properties of(90-x)Tix Zr6Al4 Fe alloys after hot rolling at 880℃ shows that with the increase of Zr content,The width of α laths gradually increase in the first three kinds of alloy and there exist fine secondary α phases.The other two alloys’ structure is made up of β coarse grains and fine needle-like α plates.The tensile strength increases while the elongation decreases gradually,of which the highest strength is 1522 MPa and the elongation is 2.68%.The result shows that the alloy element Zr has obvious strengthening effects on the alloys.While,the strength of the tested alloys after hot rolling at 850℃ is about 1300 MPa and the elongation increases from 8.8% to 10.7%.Investigation of the microstructure shows that the bimodal microstructure translate to a typical bimodal microstructure.At the same time,the microstructure of rolled alloys following normalizing at 600℃,650℃,700℃ and 750℃ was studied.The microstructure of Ti-5Zr-6Al-4Fe and Ti-10Zr-6Al-4Fe alloy after normalizing at 700℃ shows a bimodal structure which consists of equiaxed α grains and α lamellae.Nevertheless,the microstructure of Ti-15Zr-6Al-4Fe and Ti-20Zr-6Al-4Fe alloy after normalizing at 650℃ consists of residual primary β grain boundaries and fine α laths.Furthermore,the hardness of these alloys decreases gradually with increasing the normalizing temperature.