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Article: Improvement in Laser Weldability of INCONEL 738 Superalloy through Microstructural Modification
- Article from:
- Metallurgical and Materials Transactions
- Article date:
- November 1, 2009
- Author:
CopyrightCopyright Minerals, Metals & Materials Society Nov 2009. Provided by ProQuest LLC. (Hide copyright information)
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Microstructural study of laser-beam-welded IN 738 superalloy was carefully performed to better understand the causes of heat-affected zone (HAZ) cracking and to determine an improved approach of alleviating the weldability problem. The HAZ cracks in the alloy were intergranular liquation cracks that resulted from the liquation reaction of both secondary solidification products (MC carbides and γ-γ' eutectic) and solid-state reaction products (γ' particles) present in the preweld material. In contrast to the expectation based on Chadwick's equation, a reduction of grain boundary liquid film thickness did not produce a decrease in HAZ cracking owing to increased base alloy ...