Jonesite 19 - An Intermetallic Superalloy System for High Temperature Application

Conventional nickel-based superalloys are primarily strengthened by g and g’ phases to gain high temperature properties for intended applications such as jet engine and gas turbine components. For the strengthening phases, g is a fcc solid solution matrix and g’ is an ordered fcc precipitate. The precipitation of g’ phase is processed through desired precipitation heat treatment to produce most effective precipitate size and distribution to gain maximum high temperature strength. Aluminum and titanium are two alloying elements to form g’ phase, Ni₃Al and Ni₃(Al,Ti) in conventional nickel-based superalloys. The typical maximum strength for common nickel-based superalloy can be reached at about 760°C.

Alloy Jonesite 19 system is designed with fully intermetallic phases through solidification process such as casting method. The alloy matrix is composed of two intermetallic phases orthorhombic Ni₃Nb and Ni₆Nb₇. Therefore, the maximum strength of Jonesite 19 can be extended to much higher temperature such as greater than 1000°C. The relatively low thermal conductivity of Jonesite 19 can benefit its application as partial thermal barrier alloy for potential high temperature applications including Jet engine, gas turbine, and heavy-duty IC engine applications.

Jonesite 19 possesses excellent corrosion resistance, hot corrosion resistance, and wear resistance. The results of immersion/vapor corrosion test and Plint wear test has clearly exhibited the advanced high temperature properties/behaviors in alloy Jonesite 19.