Study On The Relationship Between Macroproperties And Microstructures Of Titanium Sheet Roll Forming

As a strategic structural material,titanium metal is extremely important for its research and application due to its good comprehensive properties.Roll forming has the advantages of high efficiency,low cost and high forming accuracy,and is widely used in construction,automobile,machinery manufacturing and other fields.For this reason,the roll forming process is used to process the titanium sheet.In this paper,TA2pure titanium and TB5 titanium alloy are selected,TC4 titanium alloy three kinds of sheets,through the roll forming process,to study the changes of the macro-properties(springback,hardness value)and microstructure evolution of the three kinds of sheets.The springback and hardness of roll forming sheets were studied,and the results showed that:in the single-stand roll forming experiment,with the increase of the forming angle,the springback angle of TA2 decreased gradually,and the springback angle of TB5 and TC4 increased gradually.In the roll forming experiment with a final forming angle of 30°,with the increase of the number of stands,the springback angle of TA2 gradually increased,the springback angle of TC4 gradually decreased,and the springback angle of TB5 increased first and then decreased.The microhardness analysis of roll forming of three kinds of sheets shows that the springback of TA2 is negatively correlated with the hardness,and the springback of TB5 and TC4 is positively correlated with the hardness.The microstructure of roll forming sheet was studied,and the results showed that:in the roll forming experiment,for the TA2 pure titanium sheet,the average grain size did not change much,the basal slip system was easier to start,and the main texture produced was{101~—0}<0001>,a small amount of twins are found in single-stand forming,but the twins disappear in multi-stand forming.The main reason that affects springback and hardness changes is the distribution of dislocation density.The forming angle increases,the dislocation density gradually decreases,the internal stress release decreases after unloading,and the springback gradually decreases.The final forming angle of 30°increases with the number of stands,and the dislocation density gradually increases,and the springback increases gradually;For the TB5 titanium alloy sheet,the grain size changes very little,but the grain refinement in three stands is obvious,from38μm to 27μm,because the Schmid factor is close,the<110>and<112>slips are easy to start,multi-system slip occurs,and the texture is concentrated in<111>//ND.In the single-stand experiment,with the increase of the forming angle,the dislocation density gradually increases,and the springback increases gradually.In the experiment with the final forming angle of 30°,The second stand<110>slip system is easier to start,the{001}<100>texture is enhanced,and the springback increases,and the third stand is multi-slip again,and the springback decreases;for the TC4 titanium alloy sheet,due to the crystallinity The grain size has been refined enough to only 2μm,so the average grain size is basically unchanged.In the single-stand experiment,the basal plane slip is easier to start than the primatic slip,and the main texture is<0001>//ND,as the forming angle increases,the dislocation density increases gradually,and the springback increases gradually.In the multi-stand experiment,the primatic slip starts,and the texture is concentrated in<01 1~—0>//TD.As the number of stands increases,the dislocation density gradually decreases,and the springback decreases gradually.In this paper,through the research on the macroscopic properties and microstructures of the three kinds of sheet roll forming,the springback and hardness change laws of the three kinds of sheet roll forming are analyzed,and the microscopic mechanism of the three kinds of sheet deformation is explained in detail,which is helpful for the actual processing of pure titanium and titanium alloy sheet roll forming provides experience and theoretical reference.