Densification and micro-structural characteristics of spark plasma sintered Ti-Zr-Ta powders

• Published in: Powder technology Vol. 321; pp. 471 - 478
• Main Authors: Bayode, B.L., Lethabane, M.L., Olubambi, P.A., Sigalas, I., Shongwe, M.B., Ramakokovhu, M.M.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01-11-2017; Elsevier BV
• Subjects: Alloying elements; Alloys; Bulk density; Densification; Density measurement; Dental materials; Evolution; Fabrication; Hardness; Martensite; Materials engineering; Metallurgy; Microhardness; Microstructures; Optimization; Oxygen; Plasma sintering; Powder; Relative density and hardness; Spark plasma sintering; Tantalum base alloys; Ti-Zr-Ta alloys; Titanium base alloys; Zirconium base alloys; Spark plasma sintering; Microstructures; Ti-Zr-Ta alloys; Relative density and hardness
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2017.08.031

The fabrication of Ti-based alloys with enhanced properties for extreme applications is an insatiable quest in the materials engineering field. Optimization of powder metallurgical processing routes is an area of interest for more efficient and cost effective manufacturing techniques. Ti-Zr-Ta alloys of different characteristics have been synthesized from their elemental powders, using Spark Plasma Sintering (SPS): Temperature (1100°C), Pressure (50MPa) and holding times (5min and 10min) respectively. Microstructures, chemical and phase analyses were conducted using FE-SEM, EDS, Oxygen analyser and XRD. Results revealed significant amount of martensite phase evolution irrespective of the holding time. The evolution of β-Ti phase and decrease in oxygen contents was also noticed with the addition of Ta. Relative density measurement conducted using Archimedes principle revealed the bulk samples had densifications close to theoretical values and micro-hardness of significantly high magnitudes (above 500Hv). This suggests the suitability of the fabricated products for applications requiring high hardness parameters such in dental technologies.
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•Addition of Ta ternary element resulted in improved microstructures and densification behaviour of alloys.•Increase in sintering holding time did not have significant impacts on the microstructures.•Evolution of β-phase in ternary alloys resulted in decrease in micro-hardness.