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Microstructure and properties of Ni-alloy and Ni-WC composite overlays

The microstructures and performance of Ni-based alloys and Ni-WC (nickel-tungsten carbide) composite overlays deposited by plasma transferred arc welding have been studied. The Ni-alloy overlays had similar microstructures consisting of Ni dendrites, with interdendritic Ni-based eutectics, borides and carbides. Low hardness alloy overlays contained a smaller fraction of interdendritic phases relative to the high hardness alloys. The interdendritic regions make a significant contribution to the hardness since they are more than twice as hard as primary dendrites.
The Ni-WC composites contained similar phases, however WC dissolution was observed leading to the formation of other carbides. Ni-alloys with low carbon and Cr content exhibited the lowest WC dissolution. The Ni-WC overlays produced using these dilute alloys generally performed better in ASTM G65 wear tests. This was likely due to the reduced dissolution which avoided formation of brittle secondary phases, maintaining a short mean free path between WC particles and allowing increased impact energy absorption. / Materials Engineering

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:AEU.10048/1545
Date11 1900
CreatorsLiyanage, Thilan
ContributorsGerlich, Adrian (Chemical and Materials Engineering), Nychka, John (Chemical and Materials Engineering), Mendez, Patricio (Chemical and Materials Engineering), Grondin, GY (Civil and Environmental Engineering)
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Format9231166 bytes, application/pdf
RelationLiyanage, T.; Fisher, G.; Gerlich, A.P.. "Influence of alloy chemistry on microstructure and properties in NiCrBSi overlay coatings deposited by plasma transferred arc welding (PTAW)". Surface Coatings and Technology (2010). <http://www.sciencedirect.com/science?_ob=ArticleListURL&_method=list&_ArticleListID=1479150956&_sort=r&_st=13&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=531ce42798aca015f335a828a73a8c92&searchtype=a>

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