Abstract:

Bipolar plates are one of the important components of hydrogen fuel cells. Titanium has many advantages as a metal bipolar plate substrate， but titanium has poor forming properties and severe rebound. In this paper， taking the micro channel hydroforming process of 0.1 mm TA2 pure titanium sheet as the research object， the microstructure deformation behavior of pure titanium is studied through the combination of experiment and finite element simulation， and the influence of process parameters on the forming quality of micro flow channel is analyzed， so as to provide guidance for the hydroforming of titanium bipolar plate. A finite element model has been developed for micro flow channel hydroforming of TA2 pure titanium sheet， and the accuracy of the finite element model is verified with the contours and thickness distribution of the test pieces. The effect of fluid pressure， loading rate and pulsatile loading on micro flow channel forming has been studied. The results show that the strain path of material in the process of micro flow channel hydroforming is plane strain， and the upper rounded corner position is the easiest to rupture. The loading rate does not have a great influence on the micro flow channel forming， and the molding depth decreases slightly by 3% with the increase of the loading rate. The pulsating loading path can improve the flow deformation ability of the material. Under the condition of critical fracture， the forming depth has a high increase compared with the linear loading path， which is up to 232.2 μm， an increase of 23%.

Key words: TA2, micro flow channel, hydroforming, pulsatile loading