3.2.2.3 Numerical model

A 2D longitudinal section of the 3D calculation model for MFCAM process is shown in Figure 18. The structural parameters of the model are: d is 1.2 mm, D is 4 mm; h is 1.2–2.4 mm; the substrate thickness is 6 mm, and the distance from arc to the rim of coating head is ˜5.5 mm.

In the present study, peak current Ip (voltage) and base current Ib (voltage) are 220 A (18.2 V) and 183 A (16.7 V), respectively. The proportion of peak current time in one cycle is 0.5. Thermo-physical properties of material used in this study are listed in Table 5. The contact angle, defined as the angle at which the liquid metal meets the workpiece surface, is assumed to be 90°.

A grid size (200 μm) and computational time-step (2.5 ° <sup>10</sup>–6 s) for simulations are used. It took ˜72 h to run 6 s of real-time simulation of a single-track deposition using high-performance computer of 48 ° 1.6 GHz CPU.

#### 3.3 Results and discussion
