Part I: Development of new heat source model applicable to micro electron beam welding

A three-dimensional distributed heat source model is developed to represent an electron beam as a heat source, which is novel to micro electron beam welding. The power distribution across the cross-section of the beam is represented by a Gaussian function. Along the penetration depth in the solid, the energy decay of the electrons is modelled according to the electron penetration theory proposed by Kanaya and Okayama. Further, this study presents for the first time a theoretical approach to calculate the heating efficiency of an electron beam as a function of the atomic number of the target material only.