Thermomechanical behavior of intermetallic Ni-Al-co and Ti-Al-Nb based alloys during isothermal deformation

Abstract

Different plastic deformation thermo-mechanical terms were tried out on Ni-Al-Co-based alloy in cast, prepressed and deformed conditions, and on Ti-Al-Nb-based alloy in cast and deformed conditions by yielding specimens with varying rate of deformation in interval between 10 and 70% and varying deformation temperature in interval between 900 and 1200°С. Diagrams of tensile strength and elongation upon temperature dependence in Ni-Al-Co-based alloy in cast prepressed and deformed conditions and Ti-Al-Nb-based alloy in cast and deformed conditions are designed. Application features of protective technological coating based on glass enamel in isothermal forging of workpiece are examined. The results of heat-resistance tests on Ni-Al-Co and Ti-Al-Nb-based alloys coated with different compositions of protection technological coating are shown. During the deformation these technological coatings have to be high temperature lubricant, that reduce force up to two times, necessary to deform workpiece. These protection technological coatings can be used at temperatures under 1250°С. The results of the work show, that optimal temperature for deformation intermetallic Ni-Al-Co-based superaloy workpiece were between 1140 and 1160°С. Dropping temperature below 1140°С leads to crack growing because of significant reduction of ductility. The results of the work show, that optimal temperature for deformation intermetallic Ti-Al-Nb-based workpiece were between 1150 and 1200°С.