Elastic moduli and hardness of η-Ta2N3 from nanoindentation measurements
1 LSPM - CNRS, Université Paris 13 Sorbonne Paris Cité - 99 av. J. B. Clément, 93430 Villetaneuse, France, EU
2 IUT St. Denis - 3 rue de la Croix Faron, 93210 Saint Denis La Plaine, France, EU
Received: 13 February 2015
Accepted: 6 July 2015
Nanoindentation testing was used to determine elastic moduli and hardness of η-Ta2N3, a novel stiff and hard high-pressure compound recoverable at ambient conditions. For a sample having porosity of 14% we confirmed densification of its upper layer induced by mechanical polishing: At depths we obtained higher reduced elastic modulus and higher hardness when compared with the sample without the densified layer. Using the experimental values of and of porosity we derived the shear modulus of dense η-Ta2N3 to be . Hardness of the porous η-Ta2N3 was measured to be 18 GPa and its fracture toughness estimated to exceed . The Pugh criterion suggests a high malleability of η-Ta2N3 which could explain the observed surface densification.
PACS: 81.40.-z – Treatment of materials and its effects on microstructure, nanostructure, and properties / 81.05.Je – Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides) / 62.20.-x – Mechanical properties of solids
© EPLA, 2015