• 제목/요약/키워드: superlattice

검색결과 175건 처리시간 0.034초

A Study on the Strength Characteristics of $L1_{2}-Ni_{3}Al$ Intermetallic Compound ($L1_{2}-Ni_{3}Al$ 금속간화합물의 강도특성에 관한 연구)

  • Han, Chang-Suk;Chun, Chang-Hwan;Han, Seung-Oh
    • Journal of the Korean Society for Heat Treatment
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    • 제22권1호
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    • pp.8-15
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    • 2009

  • Structural studies have been performed on precipitation hardening found in $Ni_{3}Al$ based ordered alloys using transmission electron microscopy (TEM). Tilt experiments by the weak-beam method were made to obtain some information concerning the cross slip mechanism of the superlattice dislocation. The strength of ${\gamma}'-Ni_3$(Al,Ti) increases over the temperature range of experiment by the precipitation of fine $\gamma$ particles. The peak temperature where a maximum strength was obtained shifted to higher temperature. Over the whole temperature range, the interaction between dislocation and $\gamma$ precipitates is attractive. On the temperature range of 773 K to 973 K, the dislocations in ${\gamma}'$ matrix move on (111) primary slip plane. When the applied stress is removed, the dislocations make cross slip into (010) plane, while those in $\gamma$ precipitates remain on the (111) primary slip plane. The increase of high temperature strength in ${\gamma}'-Ni_3$(Al,Ti) containing $\gamma$ precipitates is due to the restraint of cross slip of dislocations from (111) to (010) by the dispersion of disordered $\gamma$ particles.

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