The growing interest in increasing the wear resistance and hardness of surfaces that are in contact with abrasives or corrosive materials has inspired the development of several processes for creating protective coatings. In-situ laser cladding is one of the most promising of these processes. It enables the formation of a uniform coating by melting powder to form the desired composition from a pure powder component.
In this research, pure Ti, graphite, and Fe are used for in-situ laser cladding on a steel substrate to form an Fe-TiC metal matrix composite (MMC). The effect of laser parameters on both the quality of the bonding and morphology of the in-situ-formed TiC iron-based composite clad are investigated. Results show that laser parameters play a crucial role in determining the clad quality and clad microstructure. Two combined parameters, effective energy and powder deposition density, are used to study the effect of laser parameters (i.e., laser power, scan speed and powder feed rate) on the clad properties. While results indicate that combined parameters help to determine the quality limit, laser process parameters need to be taken into account in order to study the clad microstructure.
To increase the clad hardness and TiC volume fraction, C:Ti atomic ratio should increase from 45:55 to 55:45, and Fe percentages in the powder composition should decrease from 70 wt% to the 10 wt%. By varying the powder composition, a change in TiC morphology, clad microstructure and clad hardness occurs. The dilution effect is also considered in the interpretation of results.
In order to estimate wear resistance, the ASTM G65-A procedure was selected to perform tests on various clad compositions. An increased wear resistance is seen when the volume fraction of TiC is increased.
| Identifer | oai:union.ndltd.org:WATERLOO/oai:uwspace.uwaterloo.ca:10012/6148 |
| Date | 26 July 2011 |
| Creators | Emamian, Ali |
| Source Sets | University of Waterloo Electronic Theses Repository |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
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