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In situ thermal imaging and three-dimensional finite element modeling of tungsten carbide–cobalt during laser deposition

✍ Scribed by Yuhong Xiong; William H. Hofmeister; Zhao Cheng; John E. Smugeresky; Enrique J. Lavernia; Julie M. Schoenung


Publisher
Elsevier Science
Year
2009
Tongue
English
Weight
940 KB
Volume
57
Category
Article
ISSN
1359-6454

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✦ Synopsis


Laser deposition is being used for the fabrication of net shapes from a broad range of materials, including tungsten carbide-cobalt (WC-Co) cermets (composites composed of a metallic phase and a hard refractory phase). During deposition, an unusual thermal condition is created for cermets, resulting in rather complex microstructures. To provide a fundamental insight into the evolution of such microstructures, we studied the thermal behavior of WC-Co cermets during laser deposition involving complementary results from in situ high-speed thermal imaging and three-dimensional finite element modeling. The former allowed for the characterization of temperature gradients and cooling rates in the vicinity of the molten pool, whereas the latter allowed for simulation of the entire sample. By combining the two methods, a more robust analysis of the thermal behavior was achieved. The model and the imaging results correlate well with each other and with the alternating sublayers observed in the microstructure.