Reaction sintering and joining nickel aluminide to AISI 316 stainless steel by self-propagating high temperature synthesis

Abstract

Self-propagating high temperature synthesis (SHS) is a process whereby reactants are ignited to spontaneously transform to products in an exothermic reaction. The aim of this study is to propose a method to join nickel aluminide with AISI 316 stainless steel by SHS and to study the combustion synthesis of nickel aluminide. From the heat of combustion synthesis junctions were formed between annular AISI 316 stainless steel and a powder metallurgy compact of Ni and Al blends. The Al mole ratio for testing the joining grade in the initial powder mixture varied from 25 at.-% to 40 at.-%. In order to check the sufficiency of the SHS reaction, the test temperature was compared with the thermodynamic calculation values. The metallographic analysis indicated that NiAl and Ni₃Al were formed in the joint layer.