Diffusion Bonding Between Zircaloy-4 and 304L Stainless Steel in the Presence of a Eutectic

Abstract

Diffusion bonding in the solid state between the zirconium alloy (Zircaloy-4) and AISI 304L stainless steel (304L SS) was studied at a temperature of 1,050 C under a dynamic pressure in a controlled atmosphere. We discussed the morphology of the interface formed by determining the distribution of the various chemical constituents as well as the location and the identification of the different phases nature formed through due to chemical exchange reactions that occurred by diffusion through the interface. Observations and chemical analysis were performed by environmental scanning electron microscope (ESEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The junction is composed of three distinct zones formed of a solid solution (FeCr)a rich in Cr as a homogeneous edging from steel side. The type phase Zr(Fe,Cr) 2 occupies the Zone II and phase Zr 2 (Fe,Ni) Zone III between them settled the eutectic Zr a -Zr(Fe,Cr) 2 . . The observations and analysis of the fracture surfaces obtained by impact testing showed a morphology of a brittle fracture by cleavage which is located at the interface. The microhardness filiation at the interface of both materials diffusion bonded is very heterogeneous.

Microstructure evolution of diffusion welded 304L/Zircaloy4 with copper interlayer

“…[ [14,15]. In this work the C14 phase was also observed probably stabilized by the presence of chromium, nickel and copper.…”

“…An interesting point is raised by from the comparaison of the hardnesses measured in the RL to values found in the litterature on similar junction without the copper interlayer. It can be seen from Table 3 that at 1293 and 1323 K the hardness of the reaction layer can reach values of 1300 to 1400 HV [14,15] while in the present work the maximum value is 792 HV. It seems obvious that these important changes are due to the presence of copper that may change the phases in the reaction layer and their distributions.…”

“…Although many studies have been undertaken, identification and kinetics formation of some phases remain controversial [11,14]. A recent study performed on the diffusion bonding at 1323K for 45 minutes holding time, indicates a ∼700µm thick reaction layer containing many phases and revealing the presence of a transient liquid phase [15]. Based on EDX measurements, the phases were identified as the α-(Fe,Cr) solid solution, the intermetallic compound Zr 2 (Fe, Ni) and the Laves phase Zr(Cr,Fe) 2 .…”

Effect of carburizing and annealing processes in improving the Ni/WC–Co adhesion strength

“…In general, it can be concluded that the diffusion of carbon, tungsten and cobalt, and the formation of their metallic phases through the nickel coating and at the interface led to improving the interlayer adhesion and its strength as well. [24][25][26]…”

Effect of Bonding Temperature on Microstructure and Mechanical Properties of Zircaloy-4/Ti/Ag/304L Diffusion Bonded Joints

“…However, the brittle IMCs produced seriously affect the properties of the joint. 8,9) Some metals, such as Ni, 10) Ti, 11) Ta, 12) have been used as a single interlayer materials of the diffusion bonding between Zr alloys and SS. Although the direct contact between Zr alloys and SS is effectively avoided and the formation of brittle ZrFe, ZrCr, ZrNi IMCs is prevented, other unexpected IMCs can be formed like Ni 5 Zr, NiZr, TiFe 2 , Ti 2 Fe, TiCr 2 , TaFe 2 and TaCr 2 .…”