This invention relates to nickel-cobalt based alloys comprising the following elements in percent by weight: from about 0.002 to about 0.07 percent carbon, from about 0 to about 0.04 percent boron, from about 0 to about 2.5 percent columbium, from about 12 to about 19 percent chromium, from about 0 to about 6 percent molybdenum, from about 20 to about 35 percent cobalt, from about 0 to about 5 percent aluminum, from about 0 to about 5 percent titanium, from about 0 to about 6 percent tantalum, from about 0 to about 6 percent tungsten, from about 0 to about 2.5 percent vanadium, from about 0 to about 0.06 percent zirconium, and the balance nickel plus incidental impurities, the alloys having a phasial stability number N.sub.v3B less than about 2.60. Furthermore, the alloys have at least one element selected from the group consisting of aluminum, titanium, columbium, tantalum and vanadium. Also, the alloys have at least one element selected from the group consisting of tantalum and tungsten. Articles for use at elevated temperatures, such as fasteners, can be suitably made from the alloys of this invention.