Simulation Study on Crack Arrest and Healing of Melting Hole of AL6061 Alloy under Pulse Current
A16061 aluminum alloy is often used in the field of aerospace skin manufacturing.Due to the weakness of medium hardness and low strength,microcracks are prone to occur when subjected to complex loads,which affects the safety and reliability of service.pulse current is a very fast,non-equilibrium metal material micro-crack repair process,which can overcome the shortcomings of the material that is not easy to weld.In this paper,based on the existing experiments,a unilateral prefabricated crack notch model was established.The finite element simulation method was used to simulate the thermal-electric-mechanical three-field coupling numerical simulation,and the electric field,temperature field and stress field distribution of the crack area under different parameters were calculated.The'birth and death element'method was used to simulate the generation of crack arrest melting hole,and the law of size change of crack arrest melting hole under different geometric and physical parameters was obtained.The results show that the anti-crack fusion hole formed by Joule heat reduces the concentrated stress at the crack tip and inhibits the crack propagation.The temperature gradient formed by the high temperature zone in the crack area and the normal temperature zone of the matrix constrains each other to produce a huge hot-pressing stress,which causes the crack width to decrease until it heals.The initial melting hole size is proportional to the crack length and inversely proportional to the plate thickness,and the optimal size diameter is within 0.1 mm.Both the current value and the current loading time can control the growth of the melt hole.When the current value is constant,the size of the melt hole formed when the time reaches 0.12 s exceeds the optimal crack arrest size range.The research results provide a mechanism reference and simulation method for crack arrest and healing of specific metal materials.
impulse currentthermal-electric-structure couplingmolten hole sizecrack arrest and healingthermal stress field
万方数据
维普
