Investigation on microstructure and high strain rate behaviour of pure tantalum prepared by hot press and subsequent annealing treatment

ABSTRACT

Among refractory metals, tantalum has long been the primary material of use in high strain rate applications. Hot pressing (HP) is a technique to produce specimens with high density and homogeneous microstructure. The individual effect of the HP or annealing heat treatment on high strain rate properties of tantalum powder compacts has been investigated, but little attention has been paid to the combined effect of subsequent annealing. In this study, the effect of annealing on the microstructure and mechanical properties of tantalum subjected to hardness and Split Pressure Hopkinson Bar (SHPB) test was investigated. After annealing at 1100°C, the grains are coarsened, thereby hardness and upper yield strength decreased to value 199 VHN and 1833 MPa, respectively. Moreover, an obvious increase in plasticity and toughness is detected at this temperature, indicating subsequent annealing is beneficial to improve the deformation properties of HPed powder compacts; the maximum plasticity of tantalum was 31.74% after annealing.

KEYWORDS:

• Tantalum
• hot pressing
• annealing temperature
• high strain rate
• grain size

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Moeen Alaei is a PhD students. Alaei’s research interest is on heat treatment and powder metallurgy.

Gholam Hossein Borhani is a Professor. Borhani’s research interests include powder metallurgy, refractory metals and extraction.

Saeed Reza Bakhshi is a Professor. Bakhshi’s research interests include surface engineering and abrasion.

Hassan Sheikh is a Professor. Sheikh’s research interest is on metal forming and modeling.