TEM Observations of Two-Phase Microstructure Formed by Phase Separation of Gamma-Prime Precipitates in Ni-Al-Si Alloys

Tomokazu Moritani; Masahiro Ota; Takao Kozakai; Minoru Doi

doi:10.4028/www.scientific.net/MSF.561-565.2361

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Hydrogen Diffusivity and Permeability In Pd_50-xTi₅₀(Cr, Fe)_x Alloys
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Two-Phase Microstructures Formed by Phase-Separations of Ordered Precipitates in Fe-Si-V Alloys
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TEM Observations of Two-Phase Microstructure Formed by Phase Separation of Gamma-Prime Precipitates in Ni-Al-Si Alloys
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TEM Observations of Precipitation of Coherent L1₂ and D0₂₂ Ordered Phases in Ni-V-Ge Alloys
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Phase Transformations in the Metallic Materials Being Electrodeposited and their Application for the Development of Advanced Technologies for Anticorrosive Protection of Canned-Food Steel Sheet
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Development of Nanocrystalline Copper-Refractory Metal Alloys
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Surface Microstructure and Corrosion Resistance of 316L Stainless Steel after High Current Pulsed Electron Beam Treatment
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TEM Observations of Two-Phase Microstructure Formed by Phase Separation of Gamma-Prime Precipitates in Ni-Al-Si Alloys

Abstract:

The phase-separation behaviour of γ’ precipitates in Ni-7.1Al-6.7Si alloy was investigated by means of transmission electron microscopy (TEM). When the alloy is aged at 1173K, coherent spherical γ’ particles having ordered L12 structure appear in γ matrix having disordered A1 structure. When the two-phase microstructure of γ + γ’ is aged at 973K, spherical γ particles precipitate in the individual γ’ precipitates. In the course of ageing at 973K, the new γ particles grow keeping the spherical shape, their number gradually decreases and finally γ particles aging at 1173K gradually change their shape from sphere to cuboid, but do not practically change their size, i.e. such phase-separation behaviour brings the decelerated growth of γ’ precipitates.