Rare refractory metals

Class: Non-Ferrous MetalsGroup: Rare MetalsSubgroup: Rare Refractory MetalsRefractory metals are a class of metals that are extraordinarily resistant to heat and wear. Refractory metals have a melting point higher than 1650 ºС. The subgroup of Refractory Metals is divided into: Basic and Wider definition.The Basic of Refractory Metals includes the following metals: Niobium (Nb), Tantalum (Ta), Molybdenum (Mo), Tungsten (W), Rhenium (Re)The Wider definition of refractory metals consists of the following elements: Titanium (Ti), Vanadium (V), Chromium (Cr),Zirconium (Zr), Hafnium (Hf), Osmium (Os), Ruthenium (Ru), Rhodium (Rh), Iridium (Ir)In my opinion, the most promising the following Refractory metals:Niobium (Nb)

Tantalum (Ta)

Titanium (Ti)

Rhenium (Re)

Hafnium (Hf)

Zirconium (Zr)