Often referred to as hard metal tungsten carbide-cobalt (WC-Co) is characterised by an extraordinary hardness and wear resistance. It is primarily used in the production of milling, drilling and pressing/punching tools as well as surgical instruments.
tungsten cobalt alloys can be made with different binder materials. Typically, the alloy consists of tungsten and nickel with cobalt in a ratio from about 85 to 98 percent by weight and the remainder being iron. This alloy demonstrates excellent wear and impact toughness properties with high strengths and good ductility.
Alloying of tungsten has been less studied than that of some other refractory metals. EB-melted and zone-refined unalloyed tungsten, as well as other very pure forms of the metal exhibit equiaxed grains upon primary recrystallization and can be strengthened by additions of nickel, iron, molybdenum and/or other elements that increase the mechanical properties at room temperature, improve the corrosion resistance and/or resistance to thermal fatigue and/or reduce the sensitivity to hydrogen embrittlement.
The alloy can also be strengthened by additions of chromium, vanadium, zirconium and yttrium that have the effect of increasing its magnetic properties. The magnetic properties of the alloy are governed by its chemical composition and thus, it is possible to map the relationship between intrinsic and extrinsic properties/parameters.
In a WC-Co alloy with a tungsten content of about 95 to 97 percent by weight the addition of 2 percent cobalt resulted in an unexpected and dramatic improvement of the tensile strength and the Vickers diamond hardness value at a pressure of 603 to 661 D.P.N. These improved properties are important in the fabrication of kinetic energy penetrators for use by military forces.