Study On Deformation And Residual Stresses Of Titanium Alloy Sheet After Laser Shock Forming

Based on the preliminary study on LSF(Laser Shock Forming) both at home and abroad, the LSF of titanium alloy sheet is studied. The effects of the LSF parameters on the formation are investigated. The varieties in the mechanical performance and the microstructure of titanium alloy sheet after the formation are analyzed. Furthermore, the fundamental study is carried out on the large area forming and profile modeling of typical workpiece of titanium alloy by LSF. Finally, the process of LSF of titanium alloy sheet is simulated by FEA (Finite Element Analysis). The main contents and results in this paper are as follows:1. On the base of single-point shocking experiments, the influence of the main factors on the deformation of titanium alloy sheet is studied. The results show that the maximum deformation of the sheet increases in a nonlinear way with the increase of the laser energy but decreases with the increase of the inner diameter of the work support. If the pyramid mould is used, the maximum deformation decreases with the increase of the top radius of the mould.2. The residual stresses in the sheet surface are measured after the titanium alloy sheet is formed. The results show that the sheet surface residual stresses are compressive. And, the maximum compressive residual stresses and their depth increase with the increase of the laser energy. Another important factor affecting the residual stresses is the energy transfer medium.3. After observing the surface quality of laser-shocked area, it is shown that the area becomes smooth and the surface roughness obviously decreases. The microstructure becomes finer and more uniform.4. The experiments of titanium alloy sheet formation on the large area and profile modeling of typical workpiece are carried out. The results show that it is possible to apply LSF to the forming of titanium alloy sheet.5. With the FEA software-ABAQUS, the process of laser shock forming is simulated. The simulated results are consistent well with the experimental ones. This shows that the model used is correct.