Interface Characteristics in Bonding of Nickel Aluminide with AISI 316 Stainless Steel by LISHS

The article presents three different bonded joints produced by laser ignition of a self-propagating high-temperature synthesis (LISHS). The junctions were obtained between an annulus of AISI 316 stainless steel and a powder metallurgy compact of Ni and Al blends. The nickel and aluminium powders were used in three ratios of 1:1. 2:1 and 3:1. The powder compact was sintered by LISHS at the same time as the nickel aluminide and the annulus of AISI 316 stainless steel were joined. The results showed that NiAl and Ni3Al were formed in the bonded layer. Also, nickel in the nickel aluminide diffused into the AISI 361 stainless steel and iron diffused from the steel to the nickel aluminide. The alloying elements were gradually distributed. The diffusion coefficients of nickel and iron were determined using the Boltzmann-Matano method: D-Fe = 2.86 x 10(-17) and D-Ni = 9.11 x 10(-17) at Ni:Al/1:1. Both Fe and Ni were lower than those reported and nickel diffusion coefficients in different ratios were all higher than iron.