The Research Of Mechanical Behaviors And Defective Effects Of α-Fe Grain Boundary

α-Fe is considered to be one of the most attractive candidates for the first wall structural material in fusion reactor with its excellent anti irradiation swelling and corrosion resistance. As materials for wall of reactor, transmutation helium, hydrogen and other products occured during the processing of nuclear fusion, which contacted with materials of lattice atom reaction to result in irradiation swelling and micro structure changes, to cause radiation hardening, ductile brittle transition temperature and volume expansion and so on, which directly affects the reliability of the fusion reactor, and puts forward a serious challenge to the safety of the nuclear reactor. The paper focus on α-Fe grain boundary, by using molecular dynamics to simulate the tensile loading with different temperature, defect location, defect distribution to achieve the mechanical properties and analyze the defect effect to grain boundaries such as void around the grain boundary, He atoms and so on.Firstly, researched on the part mechanical properties of different perfect α-Fe grain boundaries, we found that the fracture stress, fracture strain and elastic modulus of the grain boundary strength is related to the misorientation angles, and decreasing with the temperatures increasing.Secondly, research on the tensile loading of α-Fe grain boundaries with defect, the effect of He atoms defect and the atoms evolution on grain boundaries was analyzed and the different Helium atoms distribution, temperature, void location was compared. We found that the Helilum clusters squeezed in the vicinity of the Fe atoms to form helium-void clusters with strain increasing, which diffused and connected to form microcracks, and then leads to grain boundaries fracture; The grain boundary fracture is changed from plastic fracture to brittle fracture with the increasing of He atomic distribution; and the distribution of void location has a great influence on the evolution of He atoms in the grain boundaries.At latest, the dialocation multiplication of α-Fe ∑5{310}<100> tilt grain boundaries containing void defect dislocation under tensile loading was simulated, the simulation results show: when the void is distributed far away from the grain boundary, 1/2<111> dislocation loop was emission along the close packed face 4 direction near the void; when the voids located near the grain boundaries, the 1/2<111> dislocation loop emerged form the void on the side away from grain boundary, on the side which near the grain boundary, the dislocation loop emission was depressed by the grain boundary.