| As a new type of high temperature resistant nearly α titanium alloy,BTi-6431S titaniumalloy has a good high mechanical properties and high temperature short-term creep properties, playsan important role in the high temperature environment. In room temperature,because of its lowformability,it`s difficuilt to forming it. Hot forming can reduce titanium alloys`tensile strength, andimprove the plasticity, so it is widely used. However,the study on hot formability of BTi-6431Stitanium alloy is liitle so far.So, the hot formability of BTi-6431S titanium alloy sheet is investigatedin the paper as follows:(1)Uniaxial tensile tests of BTi-6431S titanium alloy sheets have been taken at650℃~865℃,constitutive equations of BTi-6431S titanium alloy has been obtained,the microscopic structure ofthe deformed sheets has been studied.(2)With the hot forming die sheet metal,deep drawing,flanging,bulging and bending tests havebeen taken at775℃~825℃of BTi-6431S titanium alloy sheet.(3)The hot forming limited curve(FLC) of BTi-6431S titanium alloy has been obtained.(4)The BTi-6431S titanium alloy box deep drawing forming at800℃has been taken,and itverifies the hot forming performance of BTi-6431S titanium alloy.The results and the main contributions are as follows:(1)Yield strength reduce and elongation rate increase significantly with the temperatureincreased, at800℃,σ sis100MPa,δ is480%.(2)Based on the Hooke’s law and Misiolek equation, the constitutive equation of BTi-6431Stitanium alloy has been fitted, provide the basic data to numerical simulation of sheet metal.(3)The hot formability of BTi-6431S titanium alloy sheet at775℃~825℃has been acquired.Forexample,at800℃,the limiting drawing ratio is1.79,the flanging limit coefficient is0.55,the bulginghigh is17.76mm,the minimum relative bending radius is1.2.(4)The forming limit curve (FLC) at different temperatures has been gotten,combined withconstitutive model,the hot forming of box drawing has been simulated,and the box has been formedsuccessfully. |
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