| Cu resources are relatively scarce,and Zn resources have a large storage capacity.Therefore,the use of Zn alloys instead of Cu alloys as decorative materials for buildings has attracted widespread attention.Zn alloy is rolled and processed into alloy sheet and made into deformed zinc alloy has become a research hotspot.There are many deformation methods of wrought zinc alloy,including rolling,extrusion,drawing,stamping,etc.Its functions and uses mainly in clude wear resistance,corrosion resistance,structure,creep resistance,and die casting.Among zinc alloys,Zn-Cu-Ti alloy has excellent creep resistance,and also has the advantages of self-cleaning,light weight and low price,safety and non-toxicity,good ductility and corrosion resistance.However,Zn-Cu-Ti alloy sheets have not been mass-produced or in-depth research and development in my country so far.They have huge market demand and practical applications.At present,they are basically imported from overseas to fill the vacancies.This article explores the properties of the zinc-copper-titanium alloy in three aspects:melting and casting,rolling process with large deformation,heat treatment,and adding Al and Mn elements.The surface morphology and microstructure of the alloy were analyzed by SEM,EDS,XRD,metallographic microscope and other testing methods,and the corrosion resistance and mechanical properties of the alloy were explored by electrochemical workstation and universal testing mac hine.First,the casting and rolling process of the alloy was studied,and it was found that with the increase of the deformation,the corrosion resistance of the alloy was improved to a certain extent.At 95%of the deformation,the corrosion potential of the alloy was up to-1.539 V,and the self-corrosion current The lowest density is 1.39×10-4 A/cm2.The grain boundary of the alloy becomes less and less obvious as the amount of rolling deformation increases,and the rolling direction will become more an d more clear.The metallography shows that the alloy is mainly composed of a white?phase and a black?phase.The mechanical properties of the alloy can be improved by changing the content of Cu and Ti elements.The tensile strength of Zn-1.65Cu-0.15Ti can reach the highest 202Mpa.The Cu element improves the solid solution strengthening and hardness of the alloy.The addition of Ti element increases the elongation of the alloy and has the effect of refining the grain.By comparing the alloys with 0.02%,0.04%,0.05%,and 0.15%Ti content,it can be seen that as the Ti content increases,the elongation of the alloy increases.The same electrochemical analysis shows that Zn-1.65Cu-0.15Ti has a maximum corrosion potential of-1.177V and a corrosion current density of 5.476×10-4 A/cm2.Secondly,after the heat treatment process,the mechanical properties of the alloy are also greatly improved.After heat treatment at 210?,the hardness of Zn-1.65Cu-0.15Ti reached the highest value of 73Hv from the initial 46Hv.The lower the heat treatment temperature,the faster the growth rate.When homogenization annealing at 210?for 1-3h,heat treatment will increase the hardness and strength of the alloy,while the plasticity will decrease accordingly,and the hardness w ill decrease after 3h.As the holding time increases,the rate of grain growth also decreases.After2 hours of heat preservation,the dendrites were partially eliminated in the homogenization treatment,most of the coarse precipitated phases were distributed at the grain boundaries,and the precipitated phases were reduced.After heat treatment at 240?for 2h,the tensile strength of the alloy reaches the highest 217Mpa,and the elongation is increased by about20%compared with other temperatures.Through the analysis of the self-corrosion potential and the corrosion current density,it is found that the overall corrosion resistance of the Zn-Cu-Ti alloy has been reduced after heat treatment.Finally,Al and Mn are added to improve the mechanical propertie s of the alloy.After adding Al element,the mechanical properties of Zn-Cu-Ti-x Al alloy are better than that of Zn-Cu-Ti ternary alloy,especially the tensile strength of Zn-Cu-Ti-4Al is about 337Mpa,and the tensile strength is improved close to 70%.Aft er adding Mn,the mechanical properties of the Zn-Cu-Ti-x Mn quaternary alloy are better than those of the ternary alloy.When the Mn element is added at 0.1%,the tensile strength of the alloy increases from 202Mpa to about 383Mpa,an increase of nearly90%.After adding Mn and Al at the same time,compared with other quaternary alloys,the mechanical properties are not improved much,and the tensile strength is close to 400Mpa;but compared with ternary alloys,the mechanical properties are about twice as high.After adding Mn and Al elements,the corrosion potential of the alloy has been significantly increased,from-1.4V to-1.1V and the corrosion resistance has been significantly improved. |
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