Effect of titanium-based additives on the strengthening of tungsten composites

Abstract

To meet the high demand of tungsten alloy matrix wires for photovoltaic slicing, new high performance tungsten composites are explored and the effect of various Ti-based additives on the mechanical properties of tungsten is systematically discussed as well as the corresponding strength improvement mechanism. It is found that the W-TiB2 exhibits the best mechanical properties with an ultimate tensile strength of 292.3 MPa and a compressive strength of 2370 MPa (a strain of 35%), approximately 96.1% and 28.5% higher than those of pure tungsten, respectively. Besides, the TiB2 additive also triggers a slight toughening with a transgranular fracture. The enhanced strength should be attributed to the reaction between TiB2 and adsorbed/dissolved oxygen, in which a new second phase of TiO2 is generated with a small amount of Ti elements solidly dissolved into the W matrix, resulting in enhanced binding ability among grain boundaries and distorted lattices.