Development of insert metal for transient liquid phase bonding of Fe-Base heat resistant alloy

The effect of alloying elements on the joinability of an insert metal for the transient liquid phase bonding of Fe-base heat resistant alloys was investigated. The optimum chemical composition of the insert metal was found by an interpolation method. The proposed insert metals were newly developed Ni-base filler metals with B, Si and Cr. The melting point and critical interlayer width were decreased with the increase of B, Si and Cr. The optimum amounts of B, Si and Cr in the insert metal were found to be about 3%, 4% and 3%, respectively. The measured characteristic values, such as melting point, microhardness in the bonded interlayer and CIW of the insert metals show good agreement with the interpolated values. The tensile and creep rupture strengths of the joints were the same level as those of the base metal at bonding temperature over 1423K.