Abstract: Embodiments herein present the invention of a class of Tungsten (W) free Cobalt based (?-??) superalloys with the basic chemical composition comprising in % by weight: 0.5 to 10 Aluminium (Al) and 1 to 15 Molybdenum (Mo) with at least one or both of 0.5 to 12 Niobium (Nb) and 0.5 to 12 Tantalum (Ta), with the remainder being Cobalt (Co). Some part of the cobalt can be replaced by nickel (50% or less). In Nickel added alloys, some part of either cobalt of nickel can be replaced by at least one among the transition metal selected from the group consisting of 10% or less Iridium, 10% or less Platinum, 10% or less Palladium, 15% or less Chromium and combination thereof.