Investigation of a Ti–30Zr binary alloy fabricated through spark plasma sintering

Abstract

A series of Ti–30Zr alloys have been synthesized by the spark plasma sintering (SPS) process using a mixture of elemental powders processed by mechanical alloying. A sintering temperature of 900 °C was used during SPS with heating rates of 140, 200 and 350 °C min−1 with a constant load of 50 MPa. The effect of the heating rate on the densification, microstructure, phase transformation and microhardness is discussed. The sintering kinetics and the in situ densification were performed by the analysis of the punch displacement during SPS processing. Structural details of consolidated materials were evaluated by the combination of X-ray diffraction, field emission scanning electron microscopy and differential scanning calorimetry tests. Vickers microhardness of samples was also evaluated. The results show that samples reached high densification values up to 99.7% of the relative density by using lower sintering temperatures in comparison to conventional sintering techniques. Phase transformation analysis demonstrates the formation of αʹʹ and ω metastable phases without using any post-treatment. Microhardness values between 950 and 1040 HV were obtained as an effect of the SPS parameters and metastable phase precipitations.

Keywords

• Spark plasma sintering
• Mechanical alloying
• Titanium alloys
• Phase transitions
• Powder consolidation