Growth behavior of inter metallic compounds at N06200 nickel alloy and S32168 stainless steel

The evolution process of IMCs at the interface between N06200 nickel-base alloy and S32168 stainless steel TIG welded joint after post-weld heat treatment was analyzed. The formation type, sequence and growth kinetics model of IMCs at the interface were analyzed through the perspective of thermodynamics and kinetics. The results showed that with the increase of heat treatment temperature, the tensile strength of the welding joint increases firstly and then decreases. With the increasing of holding time, the tensile strength of the joint increased. The IMCs at the interface between nickel base alloy and stainless steel after welding heat treatment were mainly composed of NiFe phase, Ni₂Cr phase, FeCr phase and Ni₃Fe phase. The thickness of IMCs layer at the interface increase with the increasing of heat treatment temperature and holding time. The formation sequence of IMCs was NiFe→FeCr→Ni₂Cr→Ni₃Fe. The growth of IMCs was in line with parabolic law. The kinetic model of IMCs was W=1.725 × 10⁻¹³·e^-45.98 /(R T) \cdot t^1 / 2 . by linear regression method.