• Title/Summary/Keyword: TiAl alloys

Search Result 335, Processing Time 0.022 seconds

A Study on the Precipitation Behaviors in Rapidly Solidified AI-Li-Ti Alloys (급냉응고된 AI-Li-Ti 합금의 시효석출거동에 관한 연구)

  • Kim, Jae-Dong;Jeong, Hae-Young
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.31 no.3
    • /
    • pp.279-286
    • /
    • 1995

  • As Al-Li based alloys are to find widespread use in aerospace and other structural applications in which their low-density high specific stiffness properties be exploited, their mechanical properties must adequately match those of the which they intended to replace. In order to develop these purposed, the precipitation behaviors of the rapidly solidified Al-Li-Ti alloys aged at various temperature were investigated. ${\delta}'$ phase precipitated homogeneously in the matrix during not only melt quenching but also aging at the aging temperature of $160^{\circ}C\;and\;210^{\circ}C$. The addition of the Ti in Al-Li alloy promoted the formation of $\delta$' phase. The addition of Ti on the ${\delta}'$ solvus line had a little effect over the thermodynamics ${\delta}'$ solvus line. The reason for these behavior was that the ${\delta}'$ phase was suppressed to precipitate as much as supercooling by melt quenching. The discontinuous precipitation reaction occurred by the preferential growth of ${\delta}'$ phase due to the migration of grain boundary provided the driving force dependent of solute concentration fluctuations.

  • PDF

Mechanical Alloying Behavior and Microstructures of Extrudate in Al-Ti-(Si) Base Alloys (A1-Ti-(Si)계 합금의 기계적 합금화 및 성형체의 미세조직)

  • 최철진
    • Journal of Powder Materials
    • /
    • v.2 no.2
    • /
    • pp.165-170
    • /
    • 1995

  • Alloying behavior of nanocrystalline Al-Ti-(Si) composite powders via mechanical alloying (MA) has been investigated, and the effect of Si on the microstructural changes during MA was discussed. The microstructures of both MA powders and extruded compacts were examined. In Al-Ti system, the solid solutionized nanocrystalline powders could be obtained by MA. On the contrary, fine Si particles were embedded as an elemental state in the matrix of Al-Ti-Si system because of the brittleness and the negligible solid solubility of Si in Al. After hot extrusion, $Al3Ti$ phase was finely precipitated in Al-10fSTi alloy, and Si particles were dissolved to form $(Al, Si)_3Ti$ phase in Al-10%Ti-2%Si alloy.

  • PDF