- Measurement Uncertainty for Analysis of Residual Carbon in a Tungsten-15% Copper MIM part
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Jeong-Keun Lee
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J Korean Powder Metall Inst. 2007;14(6):410-414.
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DOI: https://doi.org/10.4150/KPMI.2007.14.6.410
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 Abstract
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- Carbon contamination from the binder resin is an inherent problem with the metal powder injection molding process. Residual carbon in the W-Cu compacts has a strong impact on the thermal and electric properties. In this study, uncertainty was quantified to evaluate determination of carbon in a W-15%Cu MIM body by the combustition method. For a valid generalization about this evaluation, uncertainty scheme applied even to the repeatability as well as the uncertainty sources of each analyse step and quality appraisal sources. As a result, the concentration of carbon in the W-Cu part were measured as 0.062% with expanded uncertainty of 0.003% at 95% level. This evaluation example may be useful to uncertainty evaluation for other MIM products.
- An Empirical Study on Drilling Characteristics of Titanium Carbide Metal Matrix Composites (1)
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Jeong-Keun Lee
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J Korean Powder Metall Inst. 2006;13(6):445-449.
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DOI: https://doi.org/10.4150/KPMI.2006.13.6.445
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Abstract
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- The experimental data from the central composite design runs were utilized for mathematical models far the drilling characteristics containing linear, quadratic and interactive effects of the parameters such as volume fraction of TiC in the composites, drill speed, feed rate and drill diameter. The models were developed via stepwise selection where the insignificant effects were removed using t-test. The models were subjected to optimization of maximizing drill life and satisfying the other constraints.
- Abrasiveness Behavior of Counterpart Sliding Against Titanium Carbide Based Metal Matrix Composite
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Jeong-Keun Lee
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J Korean Powder Metall Inst. 2006;13(6):450-454.
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DOI: https://doi.org/10.4150/KPMI.2006.13.6.450
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Abstract
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- Wear of steel plate was measured during unlubricated sliding against TiC composites. These composites consist of round TiC grains and steel matrix. TiC grain itself exhibits low surface roughness and round shape, which does not bring its counterpart into severe damage from friction. In our work a classical experimental design was applied to find out a dominant factor in counterpart wear. The analysis of the data showed that only the applied load has a significant effect on the counterpart wear. Wear rate of counterpart increased non-linearly with applied load. Amount of wear was discrepant from expectation of being in proportion to the load by analogy with friction force. Our experimental result from treating matrix variously revealed bimodal wear behavior between the composites and counterpart where a mode seems to result from the special lubricant characteristic of TiC grains, and the other is caused by metal-to-metal contact. The two wear mechanisms were discussed.
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