Study On Corrosion Behavior And Mechanical Properties Of TiZr-based Alloys

Titanium(Ti)and its alloys,due to their high specific strength,low density and excellent corrosion resistance,have broad application prospect in aerospace,watercraft and chemical industries.Ti-6Al-4V(TC4)alloy has excellent mechanical properties and has been successfully applied to commercial production.Zirconium(Zr)and Ti belong to the same group(IVB),and they have similar physical and chemical properties.New Ti-Zr-Al-V series alloys has been successfully developed by replacing part of Ti in TC4alloy with Zr.Based on the weak basic researches of Ti alloys in the fields of aerospace and marine vessels,the effects of iron(Fe)content and heat treatment process on the microstructure,corrosion resistance and mechanical properties of new TiZr-based alloys are studied,respectively.The Ti-30Zr-5Al-3V-xFe alloys are smelted by using vacuum non-consumable electro-arc furnace and then rolled at 1000~oC.The microstructure and corrosion behavior of hot-rolled alloys are studied.The results show that all the alloys were composed of?and?phase.With the increase of Fe content,the content of?phase in the alloy increases gradually.All hot-rolled alloys exhibited spontaneous passivity in 3.5wt.%NaCl and5wt.%HCl solutions,and pitting corrosion occurred with increasing the potential to 1.25V(SCE).In addition,compared to the 304 stainless steel,Fe containing alloys exhibited excellent corrosion resistance despite they present slightly inferior corrosion behavior compared to Ti-30Zr-5Al-3V alloy.The Ti-25Zr-5Al-6V alloys are also prepared by using vacuum non-consumable electro-arc furnace.The effects of rolling temperature and cooling rate on structure and mechanical properties of Ti-25Zr-5Al-6V alloys are studied.The results show that800R-AC and 950R-AC alloys,denoted alloys rolled respectively at 800~oC and 950~oC and then cooled by air,were composed of?'and?phase,however,800R-WQ and 950R-WQ alloys,denoted alloys rolled respectively at 800~oC and 950~oC and then cooled by water,consisted of?"and?phase.800R-AC and 950R-WQ alloys possesses respectively the highest tensile strength(?_b=1438MPa)and maximum elongation(?=8.05%).Based on considering the comprehensive properties of alloy,800R-WQ alloys possesses outstanding mechanical properties(?_b=1307MPa,?=7.98%).