The Helium Bubble Effect On The Mechanical Properties Of Iron-based Materials Under A Pressure Field

Because of the extremely low solubility of helium in metals, helium atoms generated mostly by (n, a) reactions of neutrons with matrix nuclei during neutron irradiation tend to be trapped at defects that create excess volume within the crystal such as vacancies, dislocations and grain boundaries. It has been observed that helium easily precipitates into clusters or bubbles. The formation of helium bubbles in materials can lead to void swelling and produces high temperature intergranular embrittlement,surface roughening and blistering. These effects would significantly degrade the mechanical properties of materials, therefore, the production and evolution of He atoms in metals are studied with particular concern.Firstly, molecular dynamics method with the Beck potential function of helium was used to simulate uniaxial tensile tests of He crystals, and the Young’s modulus, bulk modulus, and Poisson’s ratio of He crystals were computed. Then a FM model was builded, where a2D thick shell plate of CLAM alloy include He bubbles at its gran boundary. Ansys was used to simulate a stress load on the plate. In the simulation, the mechanical parameters of He bubbles are from the results of the above MD simulations and the ones of CLAM alloy are obtained from experimental data. The effect of He bubble on the mechanical properties of the CLAM alloy were studied.