Effect of hydrogen on crack propagation in magnesium
This study builds an Mg-H atomic system and investigates the influence of hydrogen atom distribution on the fracture mode and crack propagation path of single-crystal magnesium under uniaxial tensile loading using molecular dynamic simulation.The results indicate that in the pure magnesium system,due to dislocation emission at the crack tip,the crack tip exhibits the characteristic of cavitations.In the randomly hydrogen-distributed system,hydrogen atoms inhibit dislocation emission at the crack tip,and the accumulated energy at the crack tip is released through the cleavage along crystal planes.In the system with hydrogen segregation,the ultimate stress decreases with increasing volume of hydrogen segregation region,while the fracture strain increases with decreasing volume of hydrogen segregation region,and the crack propagation path involves the coalescence of cleavage cracks and cavities.The study demonstrates that hydrogen segregation can lead to a brittle-ductile mixed fracture mode in magnesium crystals,causing the delayed fracture of magnesium crystals.
万方数据
维普
