EFFECT OF C DOPING ON He BEHAVIOR IN Al

It has been verified that He embrittlement in metals could be suppressed by proper additions of alloying elements,and this effect is related to highly dispersive secondary phase precipitated in the matrix.Effect of C doping on ion implantated He behavior in Al has been investigated by XPS, XRD,TEM and SEM.It was found that the secondary phase precipitated in the surface of Al doped with C is Al_4C_3.With the increase of the dose of C,the volume of Al unit cell increased,and the preferred orientation of Al surface changed from(100) to(111),which will affect the He behavior in Al. The pre-doped C played an important role in the Al surface blistering induced by He ion implantation, and the extent is dependent on the dose of pre-doped C.When the Al sample was pre-doped by C with smaller fluence(≤5.0×10~(20) ions/m~2),the growth of blisterings is suppressed effectively,and the surface blisterings are distributed more uniformly.However,when pre-doped C has larger fluence(≥1.0×10~(21) ions/m~2),the suppression effect of C on surface blistering would be reduced,and even the irradiation damage of He ions(voids and flakings) would appear in the surface.The effect of C doping on the microstructure in Al was also observed.