Prediction of Laser Fusion Zone Profile of Lotus-Type Porous Metals by 3D Heat Transfer Analysis

Numerical Simulation of Fusion Zone Shape of Lotus-type Porous Iron by Laser Welding

“…The relation between direction of the pores and the irradiated direction of laser beam remarkably influenced weld formation for the lotus copper and the lotus magnesium [6][7][8][9] ; however, the relation effects a little change in the weld formation for the lotus iron as mentioned above. In order to clarify the reason of these results, anisotropy of thermal diffusivity in the lotus-type porous metals and anisotropy of laser energy absorption coefficient for these metals caused by multiple laser reflections on the wall of pores were estimated as follows.…”

“…Three-dimensional FEM calculation of temperature distribution of the lotus iron was performed using ABAQUS with user-defined subroutines. The detailed descriptions are given in our previous papers [6][7][8][9] . The lotus iron is modeled as an equivalent orthotropic material; Equivalent density eq T , equivalent specific heat C p eq T , and equivalent thermal conductivity parallel and normal to the directional pores, k eq // T and k eq T , with temperature dependencies are described as the following equations [6][7][8][9] .…”

“…Heat input in the specimen and heat conduction on the specimen surface also considered during laser welding. More detailed descriptions are also given in our previous papers [6][7][8][9] . The specimen size, welding speed, and spot diameter were assumed to be 20 mm (x) 10 mm (y) 2 mm (z), 1 m•min -1 , and 1.0 mm, respectively.…”

“…These were expected as innovative engineering materials because the directional pores yield various unique physical properties such as sound absorption, thermal conductivity, and electrical conductivity 3) . Therefore, laser weldabilities of the lotus-type porous copper 4) , iron 5) and magnesium 6) were investigated, and the effect of pore direction on fusion zone shape of the lotus-type porous magnesium [6][7][8][9] and copper 8,9) by using three-dimensional FEM analyses of temperature distribution during laser welding were demonstrated. These reports have pointed out that relation between direction of the pores and the irradiated direction of laser beam appreciably influenced weld formation for the lotus-type porous copper and magnesium; however, the relation had little effect on the weld formation for the lotus-type porous iron.…”

“…These are the lotus copper 2-4, 10, 11) , the lotus magnesium 3,6,[12][13][14] , and the lotus iron 5,15) . These metals exhibit different thermal conductivity parallel and normal to the directional pores [6][7][8][9]11) . In order to demonstrate the effect of this characteristic on the welding phenomena, three different combinations of relationships -pore direction, applied heat source direction, and welding direction-were considered as shown in Fig.…”