Tungsten wire

Abstract

According to one embodiment, a tungsten wire including a tungsten alloy containing rhenium, wherein, according to an EBSD analysis on a unit area of 40 μm× 40 μm in a central portion located within 100 μm concentrically extending from a central axis in a cross section along a wire radial direction perpendicular to a wire drawing direction in a main body portion of the tungsten wire, an area ratio accounted for by crystal orientations having an orientation difference of 15 degrees or less from <101>, which is parallel to the wire drawing direction, to a measurement field is 90% or more and 99.9% or less on an IPF map.

What is claimed is: 
     
         1 . A tungsten wire comprising a tungsten alloy containing rhenium, wherein, according to an EBSD analysis on a unit area of 40 μm×40 μm in a central portion located within 100 μm concentrically extending from a central axis in a cross section along a wire radial direction perpendicular to a wire drawing direction in a main body portion of the tungsten wire, an area ratio accounted for by crystal orientations having an orientation difference of 15 degrees or less from <101>, which is parallel to the wire drawing direction, to a measurement field is 90% or more and 99.9% or less on an IPF map. 
     
     
         2 . The tungsten wire according to  claim 1 , wherein, on the IPF map, an area ratio accounted for by crystal orientations having an orientation difference of 5 degrees or less from <101>, which is parallel to the wire drawing direction, to the measurement field is 88% or more and 98% or less. 
     
     
         3 . The tungsten wire according to  claim 1 , wherein, according to the EBSD analysis on the unit area of 40 μm×40 μm in an outer peripheral portion located within 50 μm from an outer periphery of the main body portion of the tungsten wire, an area ratio accounted for by crystal orientations having an orientation difference of 15 degrees or less from <101>, which is parallel to the wire drawing direction, to the measurement field is 70% or more and 93% or less on the IPF map. 
     
     
         4 . The tungsten wire according to  claim 2 , wherein, according to the EBSD analysis on the unit area of 40 μm×40 μm in an outer peripheral portion located within 50 μm from an outer periphery of the main body portion of the tungsten wire, an area ratio accounted for by crystal orientations having an orientation difference of 15 degrees or less from <101>, which is parallel to the wire drawing direction, to the measurement field is 70% or more and 93% or less on the IPF map. 
     
     
         5 . The tungsten wire according to  claim 3 , wherein, on the IPF map of the outer peripheral portion of the main body portion of the tungsten wire, an area ratio accounted for by crystal orientations having an orientation difference of 15 degrees or less from <227>, which is parallel to the wire drawing direction, to the measurement field is 3% or more and 20% or less. 
     
     
         6 . The tungsten wire according to  claim 1 , wherein, on a crystal grain map of the central portion of the main body portion of the tungsten wire, an average grain size is 0.15 μm or more and 0.23 μm or less. 
     
     
         7 . The tungsten wire according to  claim 2 , wherein, on a crystal grain map of the central portion of the main body portion of the tungsten wire, an average grain size is 0.15 μm or more and 0.23 μm or less. 
     
     
         8 . The tungsten wire according to  claim 1 , wherein, on a crystal grain map of the central portion of the main body portion of the tungsten wire, a maximum grain size is 0.8 μm or more and 2.0 μm or less. 
     
     
         9 . The tungsten wire according to  claim 2 , wherein, on a crystal grain map of the central portion of the main body portion of the tungsten wire, a maximum grain size is 0.8 μm or more and 2.0 μm or less. 
     
     
         10 . The tungsten wire according to  claim 3 , wherein, on a crystal grain map of the central portion of the main body portion of the tungsten wire and the outer peripheral portion of the main body portion of the tungsten wire, a ratio of an average grain size of the central portion to an average grain size of the outer peripheral portion is greater than 1.00 and is less than 1.20. 
     
     
         11 . The tungsten wire according to  claim 1 , wherein the tungsten alloy contains rhenium in an amount of 11 wt % or more and 30 wt % or less. 
     
     
         12 . The tungsten wire according to  claim 2 , wherein the tungsten alloy contains rhenium in an amount of 11 wt % or more and 30 wt % or less. 
     
     
         13 . The tungsten wire according to  claim 1 , wherein a diameter of the tungsten wire is 0.05 mm or more and 0.3 mm or less. 
     
     
         14 . The tungsten wire according to  claim 2 , wherein a diameter of the tungsten wire is 0.05 mm or more and 0.3 mm or less.