An Efficient Powder Metallurgy Processing Route to Prepare High-Performance β-Ti–Nb Alloys Using Pure Titanium and Titanium Hydride Powders

Abstract

Toward designing a cost-effective advanced powder metallurgy approach, we present a new insight into the efficient utilization of titanium hydride powder, together with pure Ti powder, to prepare high-strength β-titanium alloys. In the present work, Ti-40 mass% Nb alloy was prepared by mechanical alloying of a mixture of pure Ti, titanium hydride, and Nb elemental powders, followed by a carefully designed two-step spark plasma sintering. The role of relative amounts of titanium hydride and pure Ti powders during mechanical alloying, and their effect on the microstructural and mechanical properties of the Ti-40Nb alloy, have been discussed and elaborated. An increasing amount of titanium hydride results in higher powder yield and smaller resultant powder particle size. Subsequent two-step spark plasma sintering resulted in equiaxed microstructure with primarily β phase, wherein the grain size decreased with increasing amounts of titanium hydride powder. The specimen corresponding to alloys prepared using equal amounts of pure Ti and titanium hydride powders resulted in fine-grained structure, exhibiting the best combination of mechanical properties, that is, a combination of highest hardness, high strength, and high ductility.

Microstructure and Mechanical Behavior of Ti–25Nb–25Zr Alloy Prepared from Pre-Alloyed and Hydride-Mixed Elemental Powders

“…The amount of TiH 2 mixed with other elements and MM time was adjusted based on our previous work and the ball to powder ratio was maintained at 5:1 during MM. 20) The MM was carried out for 72 ks using a planetary ball mill operated at a constant speed of 200 rpm. During sintering, the MM powder was dehydrogenated at 1073 K for 7.2 ks in the SPS chamber while maintaining a high vacuum (³10 ¹3 Pa) without applying any external load to minimize the amount of hydrogen content in the final bulk specimen.…”

Influence of processing parameters on dehydrogenation of TiH2 in the preparation of Ti–Nb: A review

“…Existing studies recognise TiH 2 critical role in the production of Ti-based alloys with good mechanical properties and low elastic modulus [ 31 , 32 ]. Nonetheless, the relationship between TiH 2 dehydrogenation behaviour and the formation of β-type Ti alloys is not fully understood.…”

Characterization of Titanium Alloy Obtained by Powder Metallurgy

“…In this context, the addition of small quantities of metals, such as: Al, Sn, Mn and Fe, leads to improved wear resistance, while reducing manufacturing costs. The most used way to obtain titanium-based alloys at a lower cost is the PM technique [ 19 , 23 , 24 , 25 ]. The broad spectrum of PM processing routes provides advantages for the elaborated Ti-products: classical sintering, laser forming, powder injection molding, spraying, rapid solidification, mechanical alloying and vapor deposition [ 24 , 25 , 26 , 27 ].…”

“…The most used way to obtain titanium-based alloys at a lower cost is the PM technique [ 19 , 23 , 24 , 25 ]. The broad spectrum of PM processing routes provides advantages for the elaborated Ti-products: classical sintering, laser forming, powder injection molding, spraying, rapid solidification, mechanical alloying and vapor deposition [ 24 , 25 , 26 , 27 ].…”