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Study On Microstructure And Performance Of Induction Cladding In Situ Synthesized TiC/Ni-based Cladding Coatings

Posted on:2010-05-23Degree:MasterType:Thesis
Country:ChinaCandidate:B Y WangFull Text:PDF
GTID:2121360278961248Subject:Materials Processing Engineering
Abstract/Summary:PDF Full Text Request
In situ synthesized TiC particulate reinforced Ni-based composite claddings can be successfully achieved employing definite amount of (Ni60+Ti+C) on 45 steel by induction cladding. According to principle of thermodynamics, Gibbs free energy of every possible product of the system is calculated. The result shows that in the system, the reaction between Ti and C has the lowest Gibbs free energy and is the main reaction. It is also shown that the system can generate many oxides. Inductors are designed, for single-turn inductor, claddings can't be obtained no matter how the parameter is adjusted. The flaw of the spiral ascending manner inductor is the wide melting zone and easy to flow. But in practice, the request of preparing claddings and not flowing can be satisfied as long as the parameter is reasonable. For disk-type inductor, the strong points are the narrow melting zone and the nice appearance. According to the practice, the second design is adopted.Four claddings with different content of (Ti+C) are prepared using the inductor. The result show that only the cladding with 15%(Ti+C) can meet the requirements. So some tests are done about this cladding. There is a narrow white and bright belt at the interface of TiC/Ni cladding and fundus. In the molten zone is typical cast dentrite structure. The structure is mainly composed ofγ-Ni austenite dentrite, M23C6,TiC etc, and has a little NiO mixed together. The hardness, microhardness, wearing capacity and erosion-resistance of the claddings is better than Ni60A cladding. Friction-wear test show that the abrasion mechanism is grain abrasion Increase of TiC particulate is good to the increase of wearing capacity and erosion-resistanceAnalyze the mechanism of TiC's synthesis, firstly, Ni60 is melted, [Ti+C] is immersed in Ni-based alloy fused mass. The generation of TiC comes from the reaction Ti+C=TiC, when the weight percent of Ti and C in the fused mass comes to concentrations condition of reaction, TiC is in situ synthesis. Growth mechanism of TiC is in the form of dissolve—crystallizes. TiC has high dissolvability in Ni fused mass at high temperature, and all of it can dissolve in Ni fused mass. It will present exsolution from liquid phase and form embryos with the decrease of temperature and dissolvability. When nucleates, TiC has the same growth rate at symmetrical crystal face and is apt to form symmetrical structure.
Keywords/Search Tags:Induction cladding, In situ synthesis, TiC (titanium carbide), Mechanism
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