Characterization of the interface to diffusion bonding of zircaloy-4 and stainless steel

AbstractThe assembly of various materials by the conventional methods finds its limits in certain specific applications. We approach a study on the solid state diffusion bonding between zircaloy (Zy4) and stainless steel (304L) for an application in the sector of the nuclear power.The diffusion couples prepared underwent treatments at the temperatures ranging between 850∘C and 1020∘C in a controlled atmosphere and under dynamic pressures of contact. We give a particular attention to the morphology of the interface, formed, with the chemical reactions of exchange which proceed between two entities Zy4/304L like with the determination of the nature of the compounds formed with the interface. The observations and chemical analysis are realized by optics microscopy’s and electronics (ESEM-EDX) and with X ray diffraction (XRD). The quantitative distributions as well as the detailed localization of the basic chemical elements are defined by chemical profiles, characteristics of each element. The junction with the interface of diffusion consists of three zones distinct, formed from a solid solution αFeCr, rich in Cr in the form of a homogeneous edge, localized in steel side. The zone of the center and that of side Zy4 are two-phase. They are made up, for one, of αFeCr- Zr(Fe, Cr)2 and for the other, Zy4 side, the solid solution αZr and the intermetallic compound Zr2 (Fe1−xNix) where X is understood enters 0,15 and 0,25. The detailed results obtained, are a stepping, between those obtained from the observations and chemical analyses and radio crystallographic. The values of the measured microhardnesses give a very heterogeneous filiations to the level of the interface of the two entities