Numerical Simulation of Moving Heat Flux during Selective Laser Melting of AlSi25 Alloy Powder

Cong Ma,Pengfei Yan,Xianshun Wei,Biao Yan

doi:10.3390/met10070877

Abstract

A single-layer three-dimensional model was created to simulate multi-channel scanning of AlSi25 powder in selective laser melting (SLM) by the finite element method. Thermal behaviors of laser power and scanning speed in the procedure of SLM AlSi25 powder were studied. With the increase of laser power, the maximum temperature, size and cooling rate of the molten pool increase, while the scanning speed decreases. For an expected SLM process, a perfect molten pool can be generated using process parameters of laser power of 180 W and a scanning speed of 200 mm/s. The pool is greater than the width of the scanning interval, the depth of the molten pool is close to scan powder layer thickness, the temperature of the molten pool is higher than the melting point temperature of the powder and the parameters of the width and depth are the highest. To confirm the accuracy of the simulation results of forecasting excellent process parameters, the SLM experiment of forming AlSi25 powder was carried out. The surface morphology of the printed sample is intact without holes and defects, and a satisfactory metallurgical bond between adjacent scanning channels and adjacent scanning layers was achieved. Therefore, the development of numerical simulation in this paper provides an effective method to obtain the best process parameters, which can be used as a choice to further improve SLM process parameters. In the future, metallographic technology can also be implemented to obtain the width-to-depth ratio of the SLM sample molten pool, enhancing the connection between experiment and theory.

Highlights

As one of the most widely-investigated fabrication techniques, selective laser melting (SLM) has outstanding advantages in obtaining 3D metal parts with high density and dimensional precision [1,2], which ensures the direct forming of thin-walled parts and complex precision parts [3,4]
The results indicate that the width and depth of the molten pool are significantly affected by the power, while the indicate the remains width and depth the of the molten pool aremelting significantly affected by the power, while scanningthat speed basically same
The results show that the size of the molten pool is maximized under the parameters of P = 180 W and v = 200 mm/s, and the actual forming effect may be better

Summary

Introduction

As one of the most widely-investigated fabrication techniques, selective laser melting (SLM) has outstanding advantages in obtaining 3D metal parts with high density and dimensional precision [1,2], which ensures the direct forming of thin-walled parts and complex precision parts [3,4]. During the SLM process, the model is sliced into two-dimensional data in the post-processing software, in order to be recognized and imported to the equipment. Under the protection of the inert gas atmosphere, the laser beam is utilized to scan the contour of the slicing model on the powder bed. The remarkable flexibility of SLM techniques gives access to the improvement of mechanical properties and aluminum alloys quality [8,9]. Considering advantages in regard to convenient utilization of traditional manufacturing facilities and reduction of cycle time, SLM technology gradually becomes critical hotspot [10,11]

Methods

Results

Conclusion