| Abstract |
| In this research, we studied the effects of Ni, Ti, and B on the elastic modulus of hypereutectic Al-Si alloys and successfully synthesized 100 GPa Al casting alloys by designing various alloys phases. Generally, Al-Si based alloys are known in the automotive industry to be good casting alloys with high wear resistance, low thermal-expansion coefficient, good corrosion resistance at a wide range of temperatures, especially for cylinder blocks, cylinder heads, pistons and valve lifters, but the low elastic modulus of the alloys remaines a weakness. Previously, the elastic modulus of eutectic Al-Si casting alloys was enhanced by 10 GPa by strengthening phases with added Ti and B. However, elastic modulus was not enhanced by increasing Si content in the hypereutectic Al-Si alloys, since Si only reacts with the Ti containing strengthening phase. We overcame this problem by adding Ni to Ti and B containing hypereutectic Al-Si alloys. The effects of the strengthening phases produced by the addition of Ni, such as AlNi, AlNiCu, on the elastic modulus were studied, and we observed a two-fold enhancement in the wear resistance of the Ni, Ti, and B containing hypereutectic Al-Si alloys. The rate of strengthening by phases in the alloys was qualitatively analyzed by EPMA (Electron probe micro-analyzer), SEM (Scanning Electron microscopy), etc, and their mechanical properties were quantitatively evaluated by elastic modulus measurement and pin-on tester.
(Received July 5, 2017; Accepted September 13, 2017) |
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| Key Words |
| elastic modulus, Al alloy, reinforcement, Ni addition, wear resistance |
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