Microstructural Characterization of Laser - Clad Nickel Aluminum Bronze Alloys by TEM

Abstract

Recently, the use of high power lasers for surface melting and cladding of nickel aluminum bronze (NAB) components has stimulated renewed interest in the microstructural development of these alloys. In this study, a laser-clad NAB weldment of nominal composition Cu 9 wt. % Al 5 wt. % Ni 4 wt. % Fe 1 wt. % Mn, provided by DREA was examined using transmission electron microscopy. Significant variations in the microstructure were observed between the weld deposit and heat affected zone of the clad. In the weld deposit, the microstmcture predominantly consisted of two phases which are the product of martensitic or possibly bainitic phase transformations. A high density of Fe-rich precipitates, ranging up to 200 nm in size, are also distributed throughout both matrix phases. In the heat affected zone, the microstmcture typically contained three major phases: a martensitic phase similar to that observed in the deposit region, the fc;:c a phase, and an (a + K) eutectoid. The small Fe-rich precipitates are retained in the martensitic phase. The observed phase relationship and morphologies will be discussed in terms of the transformation behaviour of the NAB clad.

Cite this paper

@inproceedings{Bennett2000MicrostructuralCO, title={Microstructural Characterization of Laser - Clad Nickel Aluminum Bronze Alloys by TEM}, author={J . C . Bennett and C . V . Hyatt}, year={2000} }