MICROSTRUCTURAL CHARACTERIZATION OF LASER-CLAD NICKEL ALUMINUM BRONZE ALLOYS BY TEM

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Authors
  1. Bennett, J.C.
  2. Hyatt, C.V.
Corporate Authors
Acadia Univ, Wolfville NS (CAN) Dept of Physics;Defence Research Establishment Atlantic, Dartmouth NS (CAN)
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 - 9wt. % Al - 5wt. % 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 microstructure 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 microstructure typically contained three major phases: a martensitic phase similar to that observed in the deposit region, the fcc alpha phase, and an (alpha + kappa) eutectoid. The small Fe-rich precipitates are retained in the martensitic phase. The observed phase relationship and morphologies will be discused in terms of the transformation behaviour of the NAB clad.
Report Number
DREA-SR-97-002-PAP-17 — CONTAINED IN 98-00986
Date of publication
01 Oct 1997
Number of Pages
19
DSTKIM No
98-01003
CANDIS No
507220
Format(s):
Hardcopy;Document Image stored on Optical Disk

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