Effect of tantalum concentration on the microstructure and mechanical properties of novel W–Ta-Re alloy

Abstract

Novel homogeneous and compact W–Ta-Re alloys with different concentrations of Ta were fabricated by spark plasma sintering. The effect of Ta concentration on the microstructure and mechanical properties of W-xTa-10 wt%Re (x = 0, 10, 20, and 30 wt%) alloys was studied. The single body centered cubic (BCC) phase W–Ta-Re matrix is formed by solid solution, and the grains are effectively refined with the addition of Ta. Attributing to the grain refinement and solution strengthening, the alloys exhibit excellent strength and good ductility. The average grain size reduces to 6.7 ± 2.5 μm after the addition of 30 wt% Ta, whereas it is 17.3 ± 5.5 μm for the W–Re matrix without the addition of Ta. In addition, its yield strength increased to 1248.8 ± 13.2 MPa, an enhancement by ∼183%. The ultimate compressive strength and strain rate for alloys are greater than ∼2940 MPa and ∼42%, respectively. With increasing Ta content, the matrix deteriorates because of hard oxides, causing transgranular cleavage fracture. The preferred orientation of grains along the compression direction is < 111> and <001> after deformation. The deformed structure showed several short curved and entangled dislocations, guaranteeing better mechanical properties. This research is of great significance for the strengthening and toughening of tungsten materials.