Tantalloy (tantalum-tungsten alloy), Tantalum Alloy wire (97.5/2.5 Ta/W)
Material : tantalum 2.5% tungsten alloy wire.
according to ASTM B365 92 R05252.
Chemical composition: 
                Ta    Remainder
                W     2.5-3.0%,
                C      0.010 %max
                O      0.015 %max
                N      0.010 %max
                H      0.002 %max
                Nb     0.500 %max
                Fe     0.010 %max
                Ti      0.010 %max
                Mo     0.020 %max
                Si      0.005 %max
                Ni      0.010 %max
Size available : Diameter 0.15mm up to 6.0mm x coil (at random length).
Typical size:
0.60MM(±0.019) Diameter x coil, 0.005 kg/m;
0.025"(±0.00075) Diameter = 0.6350MM(±0.019) x coil, 0.005 kg/m;
0.026"(±0.00075) Diameter = 0.6604MM(±0.019) x coil, 0.006 kg/m;

0.032"(±0.0010) Diameter = 0.8128MM(±0.025) x coil, 0.009 kg/m;
0.033"(±0.0010) Diameter = 0.8382MM(±0.025) x coil, 0.009 kg/m;
0.037"(±0.0010) Diameter = 0.9398MM(±0.025) x coil, 0.012 kg/m;

0.040"(±0.0010) Diameter =1.0000MM(±0.025) x coil, 0.013 kg/m;
0.045"(±0.0010) Diameter =1.1430MM(±0.025) x coil, 0.017 kg/m;
0.046"(±0.0010) Diameter =1.1684MM(±0.025) x coil, 0.018 kg/m;
0.048"(±0.0010) Diameter =1.2192MM(±0.025) x coil, 0.019 kg/m;
0.059"(±0.0010) Diameter =1.4986MM(±0.025) x coil, 0.029 kg/m;

0.060"(±0.0015) Diameter =1.5240MM(±0.0381) x coil, 0.030 kg/m;
0.062"(±0.0015) Diameter =1.5748MM(±0.0381) x coil, 0.032 kg/m;
0.0625"(±0.0015) Diameter=1.5875MM(±0.0381) x coil, 0.033 kg/m;
0.063"(±0.0015) Diameter = 1.6002MM(±0.0381) x coil, 0.033 kg/m;
0.064"(±0.0015) Diameter =1.6256MM(±0.0381) x coil, 0.035 kg/m;
2.0MM(±0.0381) Diameter x coil, 0.052 kg/m;
0.080"(±0.0015) Diameter =2.0320MM(±0.0381) x coil, 0.054 kg/m;
0.093"(±0.0020) Diameter =2.3622MM(±0.051) x coil, 0.073 kg/m;
2.50MM(±0.051) Diameter x coil, 0.082 kg/m; 

Trade names : TaW2.5 alloy, Ta10W (97.5%Tantalum, 2.5% tungsten) wire, Tantal 2,5% Wolfram wire, Tantal 2.5% Wolfram wire, Tantal 2,5 % Wolfram wire, tantalum tungsten alloy wire, tantalum alloys, Tantal 2,5 Wolfram, Tantal 2,5 % Wolfram, Tantalum-Tungsten wire TaW2.5, TaW2.5 wire, Ta-97/W-2.5 %wt , Ta-97.5/W-2.5  %wt , Ta-W, Ta 2.5% W wire,  97.5 Ta 2.5 W alloy wire, tantalum 2,5 Tungsten wire, etc.,