Influence of Tantalum on phase stability and mechanical properties of WB2. (4th February 2019) - Fuger, Christoph
Abstract: Abstract : Based on density functional theory, we recently suggested that metastable α -WB2 is a promising candidate combining very high hardness with high toughness. These calculations further suggested that the addition of Tantalum supports the crystallization of α -structured W1− x Ta x B2− z, with only minor reduction in toughness. Thus, various Ta containing WB2 -based coatings have been synthesized using physical vapor deposition. With increasing Ta content, the hardness increases from ~41 GPa (WB2 ) to ~45 GPa (W0.74 Ta0.26 B2 ). In situ micromechanical cantilever bending tests exhibit fracture toughness K IC values of 3.7 to 3.0 MPa√m for increasing Ta content (single-phased up to 26 at.% Ta).