Fracture behavior of squeeze-cast aluminum-nickel composites for diesel engine piston rings
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Fig. 7—Vickers hardness vs depth from the softfaced brass layer to the substrate.
4. Metals Handbook, 9th ed., ASM, Metals Park, OH, 1979, vol. 2, pp. 275 and 322. 5. L.P. Karjalainen, V.P. Kujanpa¨a¨, and N. Suutala: Advances in Welding Science and Technology, S.A. David, ed., ASM, Gatlinburg, TN, 1986, pp. 145-49. 6. C.D. Lundin, R. Menon, J.A. Henning, and M.W. Richey: Advances in Welding Science and Technology, S.A. David, ed., ASM, Gatlinburg, TN, 1986, pp. 585-95. 7. T.P. Quinn, R.B. Madigan, M.A. Mornis, and T.A. Siewert: Weld. J., 1995, vol. 74, pp. 115s-120s. 8. B. Dixon and K. Hakansson: Weld. J., 1995, vol. 74, pp. 122s-132s. 9. Metals Handbook, 9th ed., ASM, Metals Park, OH, 1983, vol. 6, p. 31.
Fracture Behavior of Squeeze-Cast Aluminum-Nickel Composites for Diesel Engine Piston Rings SUNGHAK LEE, SEONG-HUN CHOO, and MEUNGHO RHEE Composite materials have been developed to overcome the restrictions inherent in original materials by adding reinforcements to them, and to take advantage of desired properties of matrix and reinforcement simultaneously. In the early stage of the composite development, much attention was paid to polymer matrix composites. Due to the
SUNGHAK LEE, Professor, and SEONG-HUN CHOO, Research Assistant, are with the Center for Advanced Aerospace Materials, Pohang University of Science and Technology, Pohang, 790-784 Korea. MEUNGHO RHEE, Principal Research Scientist, is with the Korea Automotive Technology Institute, Chunan, 333-910 Korea. Manuscript submitted July 30, 1997. METALLURGICAL AND MATERIALS TRANSACTIONS A
Fig. 2—Optical micrographs of the A specimen (aluminum-nickel composite piston ring), showing (a) nickel foam, primary silicon particles, and eutectic silicon particles and (b) a layered structure along the Ni/Al interface. VOLUME 28A, DECEMBER 1997—2773
Fig. 4—Optical micrograph of the B specimen, showing Kaowool short fiber, nickel powder, primary silicon particles, and eutectic silicon particles.
Fig. 3—(a) through (c) EDS spectra obtained from the areas marked A, B, and C, respectively, in Fig. 2(b).
Table I.
Microvickers Hardness of the A and B Specimens Microvickers Hardness (VHN)
Phase
A Specimen
B Specimen
Matrix (Al-Si base) Primary Si particles NiAl3 Ni (center of the foam) NiAl (interface) NiAl3 (interface)
125 1078 598 230 297 655
129 1205 599 230 — —
limitations of these materials in the high-temperature applications, however, active studies are being made currently on metal matrix composites. Because aluminum matrix composites, in which nickel is added in a foam or powder shape, show far superb properties in high-temperature, wear, and corrosion resistance compared to commercial aluminum alloys, they are widely used in piston rings for automotive diesel engines. Considering the increasing demands for lightweight metals with excellent wear resistance, strength, and toughness, the application of aluminum-nickel composites is expected to be further expanded in the future. 2774—VOLUME 28A, DECEMBER 1997
These composites for piston rings are fabric
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