Optimization of Parameters for Pressureless Sintering of Titanium and Ti-6Al-4V Powders by a Taguchi Method

This work describes the effects of various parameters on the pressureless sintering of Ti and Ti-6Al-4V alloy powders. Specific sintering trials were carried out based on a Taguchi method using four parameters (particle size, compaction pressure, sintering temperature and holding time). Each parameter was studied at three different levels. The effect of sintering parameters on densification is discussed for three different materials (Ti-200mesh,Ti-6Al-4V-200mesh and Ti-6Al-4V-100mesh). Confirmation experiments were carried out to validate the optimum parameters obtained from the original design experiments. Phase constituents and microstructure were characterized using X-ray diffraction (XRD) and environmental scanning electron microscopy (ESEM). Optimum sintering parameters for achieving the highest density were 1250 degrees C and 8 hours of holding time for Ti powder, and 1400 degrees C and 6 hours for Ti-6Al-4V powder. Validation trials confirmed the optimized parameters with Ti-6Al4V-200mesh samples having density close to 95%. The additional analysis showed differences between the surface and centre of the samples, in terms of different phases, morphology and porosity.