MICROSTRUCTURAL CHARACTERIZATION OF NiAl BRONZE WELDMENTS

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Authors
  1. Gianetto, J.A.
  2. Sahoo, M.
  3. Letts, M.W.
  4. Bibby, C.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN);Metals Technology Labs, Ottawa ONT (CAN)
Abstract
The objective of this study was to develop and evaluate a series of simulation techniques to provide a better understanding of the transformation behaviour of both the weld metal and heat-affected zone (HAZ) regions formed in Ni-Al bronze (NAB) weldments. The welds investigated were produced by (i) laser cladding, (ii) gas-tungsten-arc welding (both autogenous and with filler-wire), and (iii) a Gleeble 2000 weld simulator. In the latter case the aim was to develop melting and reheating experiments that would accurately simulate the HAZ and weld metal regions found in the laser clad weldments. Optical microscopy and microhardness surveys wer eused to characterize the structures formed in the real and Gleeble simulated weldments. In addition, radial dilatometry was performed to assist with the interpretation of the complex microstructures formed as a result of dynamic thermal cycling. In general, the microstructures formed in NAB weldments were found to be strongly dependent on the alloy composition, particularly A1 content, and the thermal cycle conditions including the heating rate; peak temperature, hold time and cooling rate. In addition, there is evidence to suggest that the original starting microstructure e.g. base metal, weld metal or HAZ plays an important role in the formation of the final microstructure. TRUNCATED
Keywords
HAZ (Heat affected zone);Physical simulation;Nickel aluminum bronzes
Report Number
DREA-CR-95-435;MTL-95-3(TR-R) — Contractor Report
Date of publication
01 Jun 1995
Number of Pages
45
DSTKIM No
98-00141
CANDIS No
506840
Format(s):
Hardcopy;Document Image stored on Optical Disk

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