Analyzing the Debinding Step of Ti64 Parts Fabricated by 3D Printing Extrusion

Abstract

The aim of this work is to analyze the effect of the heating rate used during the debinding step on the consolidation of parts fabricated by additive manufacturing using the 3D printing extrusion of Ti64 samples. The cylindrical samples print by extruding MIM pellets of Ti64 mixed with a binder. Dilatometry tests follow the densification of the samples by using three different heating rates during the heating stage. All the samples then undergo the same thermal cycle of sintering. SEM and XRD analyze the microstructure. Microhardness and compression tests evaluate the mechanical properties of the sintered samples. We analyze the corrosion behavior under Hank’s solution. The results indicated that the heating rate used during the debinding step affects the densification by reducing this as the heating rate increases. After sintering, a lower relative density is reached, resulting in decreased mechanical properties and corrosion resistance. The Young’s modulus and yield strength correspond well with those of the Ti64 samples prepared by other techniques with similar porosities. Despite the remaining porosity, the parts fabricated by SLM had worse corrosion behavior than ours. The main conclusion is that the isothermal step during debinding is not necessary to ensure complete binder elimination, which will reduce the process time and thus, the fabrication costs of parts by this technique.