Anomalous elastic behavior of tantalum at high pressures: Experimental and theoretical studies. (December 2021)

• Record Type: Journal Article
• Authors: Qi, Xintong; Wang, Siheng; Chen, Sibo; Cai, Nao; Li, Baosheng
• Is Part Of: International journal of refractory metals & hard materials. Volume 101(2021)
• Publication Date: 2021-12
• Subjects: Tantalum -- Sound velocity -- High pressure -- Elastic properties; Heat resistant alloys -- Periodicals; Refractory materials -- Periodicals; Metallography -- Periodicals; Alliages réfractaires -- Périodiques; Matériaux réfractaires -- Périodiques; Métallographie -- Périodiques; Heat resistant alloys; Metallography; Refractory materials; Periodicals; Electronic journals; 669.73
• DOI: 10.1016/j.ijrmhm.2021.105691
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: Elastic wave velocities of polycrystalline tantalum have been measured up to 13.6 GPa at room temperature using ultrasonic interferometry technique in a multi-anvil apparatus. The bulk and shear moduli, as well as their pressure derivatives are obtained using Eulerian 3rd order finite strain equations, yielding K S 0 = 193.9(29) GPa, G 0 = 69.3(10) GPa, K S 0 ′ = 3.18(5) and G 0 ′ = 0.88(1). The Steinberg-Guinan yield stress model is examined using the current shear modulus and its pressure derivative, where a slightly lower A 0 = 0.0127 GPa −1 compared to previous studies is obtained. First-principles calculations on the elasticity of tantalum have also been performed up to 200 GPa. Anomalous softening of the elastic shear constant C 44 and shear wave velocity V S is observed between 80– 180 GPa, whereas the anisotropy shows a softening-stiffening behavior with increasing pressure and reaches a minimum at around 150 GPa. Such anomalies might commonly originate from the nesting of Fermi surface for Group VB metals. Highlights: Ultrasonic interferometry technique was applied to measure the sound velocities of Ta. Bulk and shear moduli of Ta and their pressure derivatives were presented. Anomalous softening of the elastic shear properties was studied by DFT calculations.