Crystal structure changes in the Ni3Ta intermetallic compound

Abstract

The crystal structure changes in Ni 3 Ta were experimentally investigated by X-ray powder diffraction of alloys prepared by arc melting, ground and annealed in the temperature range 673-1173 K for 1 day. It was found that an increase of the annealing temperatures leads to a change of the product of the transformation of the high-temperature tetragonal phase from monoclinic to orthorhombic. The changes are promoted by recovery and recrystallization processes. Some oxidation at the higher annealing temperatures led to the reappearance of the phase with monoclinic structure.

Investigation of Structural Properties and Martensitic Phase Transformations in Heat-treated Ni-25.5 at. %Ta High Temperature Shape Memory Alloys

“…However, XRD pattern of NiTa-1000 sample also includes peak positions of the all phases are also in accordance with the literature [7,8,15,16] and the corresponding phases are marked on patterns. Also, as expected, all samples contained austenite phase at room temperature [11,13,17]. The XRD pattern of NiTa-0 sample display in Fig.…”

“…Ni3Ta. Likewise, Kosorukova et al [13] reported that as aging temperature increased the stable orthorhombic Ni3Ta phase was formed in the Ni3Ta alloy, as a result of diffusional phase transformation mechanism. Consequently, the results indicated that heat treatment performed at 1000 o C led to starts diffusional phase transformation in the Ni-25.5Ta (at.%) alloy.…”

Isothermal Sections of the Ni-Cr-Ta Ternary System at 1200 °C and 1300 °C

“…The Ni-Ta binary system has been investigated by many researchers [17][18][19][20][21][22][23][24][25][26][27][28][29][30]. In 2018, Zhou et al [30] reviewed the Ni-Ta system, where only four intermetallic compounds Ni 2 Ta, Ni 3 Ta, NiTa, NiTa 2 , and two terminal solid solutions fcc-(Ni), bcc-(Ta) coexisted, and the Ni 8 Ta was confirmed to be a metastable phase.…”

Effect of Heat Treatment on the Structural Properties and Martensitic Transformation of Ni-26.5at. %Ta High Temperature Shape Memory Alloy

“…In the last years, among many high temperature SMAs, the Ni-Ta alloy has increasing interest and its structural and morphological properties, martensitic transformation behaviour and shape memory effect has been studied depending on its composition [11], by adding third alloying elements [9,10] and under predeformed states [7,8]. However, the Ni-Ta alloy system has some disadvantages: cracks in microstructure [7] and tetragonal austenite phase at room temperature with high volume fraction [13]. It has been seen that the crack problems in the Ni-Ta alloy could be tackled with changing homogenization conditions [11].…”