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
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:AEU.10048/1545 |
| Date | 11 1900 |
| Creators | Liyanage, Thilan |
| Contributors | Gerlich, Adrian (Chemical and Materials Engineering), Nychka, John (Chemical and Materials Engineering), Mendez, Patricio (Chemical and Materials Engineering), Grondin, GY (Civil and Environmental Engineering) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 9231166 bytes, application/pdf |
| Relation | Liyanage, 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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