Investigation on Ti-6Al-4V Microstructure Evolution in Selective Laser Melting

Ling Ding,Feng Li,Zhonggang Sun,Zulei Liang,Hui Chang,Guanglong Xu

doi:10.3390/met9121270

Abstract

Selective laser melting (SLM) is an advanced additive manufacturing technique that can produce complex and accurate metal samples. Since the process performs local high heat input during a very short interaction time, the physical parameters in the solidification are difficult to measure experimentally. In this work, the microstructure evolution of Ti-6Al-4V alloy in additive manufacturing was studied. With the increase of scanning speed, the cooling rate and the temperature gradient of molten pool position increased, which was attributed to the gradual decrease of energy density. The phase-field simulation resulted in the overall microstructure morphology of columnar crystals owing to the very large temperature gradient and cooling rate obtained from the temperature field. Microsegregation was observed during dendritic formation, and the solute was enriched in the liquid phase near the dendritic tip and between the dendritic arms due to the lower equilibrium distribution coefficient. The scanning speed had an effect on the dendrite spacing.

Highlights

Additive manufacturing technology has broken through the traditional material reduction manufacturing method, which relies on multiple processes combined in manufacturing
Selective laser melting (SLM) forming technology is a technology based on the principle of additive manufacturing, which enables the manufacture of parts from bottom to top through layer-by-layer stacking of materials
The study shows that combining the finite element model with the phase field model can obtain

Summary

Introduction

Additive manufacturing technology has broken through the traditional material reduction manufacturing method, which relies on multiple processes combined in manufacturing. Selective laser melting (SLM) forming technology is a technology based on the principle of additive manufacturing, which enables the manufacture of parts from bottom to top through layer-by-layer stacking of materials. Thijs et al [9,10,11,12] studied the influence of the scanning parameters and scanning strategy on the microstructure. The method of simulation is in common element additive manufacturing, thefinite temperature field distribution the additive use. Through the combination of macroscopic finite element simulation and microscopic field processed by SLM was unattended. Through the combination of macroscopic finite elementphase simulation simulation, this phase paper field attempts to bring the influence macroscopic parameters into the and microscopic simulation, this paper attempts of to bring the influence of macroscopic microstructure

Model Description

Model of Rapid Solidification Finite Element

Model of Phase Field

Finite

Conclusions