Diffusion Bonding Behavior Of Al & Ti Alloy Under High Magnetic Field

In this paper, 1420 aluminum alloy and TC4 titanium alloy which are both widely used in the aerospace field are studied. The former underwent heat treatment in a strong steady magnetic field which has simple mathematical form to research the influence of magnetic field on diffusion from the scientific level. The latter went through diffusion bongding driven by a strong electromagnetic force produced by strong pulsed magnetic field to explore using the electromagnetic force to replace the traditional mechanical, inflatable pressure to achieve a reliable connection between alloys from the technical level.Our study shows after adding a strong magnetic field, the grain size of aluminum side was increased and aluminum alloy side was just the opposite; EBSD analysis shows no obvious orientation was found on the that aluminum alloy side whether there was a magnetic field or not; The weak texture of rolling Al plain got strengthened slightly in a strong magnetic field; The concentration- distance curve achieved by EDS analysis shows a typical one-dimensional semi-infinite diffusion couple diffusion results. Diffusion coefficient under different magnetic conditions calculated by Boltzman-Matano plotting shows that a transverse magnetic field can result in an obvious inhibitation on diffusion coefficient, which is in complete agreement with other existing results. This can be interpreted semi-quantitatively by using a theory combining magneto resistance and ambipolar diffusion theory.Discharge frequency and the discharge voltage of pulsed magnetic field as well as experimental temperature can promote the diffusion bonding process of titanium alloy, which can be seen from a reduction of holes around the welding bead, a promotion of joint shear strength, an increase of tearing area, an enhancement of diffusion distance as well as diffusion coefficient of Al, etc. This effect is saturated when the discharge frequency is 10 times and the discharge voltage is 9KV. The highest shear strength is about 400MPa; the powerful electromagnetic force is the reason of this promotion. The strong electromagnetic force can make the sample better combined in macroscopic view; on the other hand, heterogeneous magnetization energy was induced microscopically because the magnetic field is not static, and this can cause an additional atom flow.