Study On Hot Deformation Rule Of TA15Titanium Alloy

TA15titanium alloy is a kind of near titanium alloy, it is widely used in Aeronautics andAstronautics. However, the yield ratio of TA15alloy is high under room temperature, the springbackis serious and forming stability is relative bad while forming, so it’s difficult to form under the roomtemperature. Hot forming is the effective method to solve this problem In some precision formingprocess, in order to improve the accuracy of workpieces, it’s usually need to carry onforming-calibrate. In order to reasonably formulate the process of hot forming and forming-calibrateand improve the quality of products, it’s necessary to study the hot forming rules and analyze the flowstress and stress relaxation of TA15titanium alloy sheet under the different temperature. Hotdeformation rules of TA15titanium alloy were studied through the method of combined withtheoretical analysis, experimental research and numerical simulation.Uniaxial tensile tests of TA15titanium alloy sheet have been taken at675℃~800℃, the truestress-strain curve, the index of basic forming ability, such as yield strength, elongation, n value and rvalue and constitutive equations of TA15titanium alloy have been obtained. Microscopic structure ofthe deformed sheets under different temperature has been studied.Stress relaxation tests for TA15titanium alloy sheet were carried under the condition of differentthermal deformation at600℃~700℃, the stress-relaxation curves and stress relaxation equation wereobtained. The suitable forming temperature is700℃and the reasonable forming-calibrate time is25minutes. The process parameters process provide a basis for the formulation of forming-calibrate ofTA15titanium alloy.Hot stamping simulation formability tests of TA15titanium alloy sheet were carried, theindicator of stamping formability such as limit drawing ratio, minimum relative bending radius, cupdrawing value and flanging limit factor were obtained.Forming limit tests for TA15titanium alloy at725℃~775℃were taken referring to the methodof FLD standard at room temperature, the FLD left dates were obtained by uniaxial tensile tests andthe right dates were obtained by using high pressure gas blown up test. The FLD at the temperature of725℃、750℃and775℃were obtained.Through the above research, the hot forming of quadrate-tapered part was simulated, and theverification tests were taken. The simulation result has better tally with test result.