Research on Microstructure and Heat Treatment of Ni3Al Alloy Formed by Laser Direct Deposition
The microstructure of high-boron Ni3Al alloy formed by laser direct deposition and the effect of heat treatment on the alloy were studied.The results show that the microstructure of laser-deposited Ni3Al alloy is mainly composed of γ+γ'eutectic phases,γ'phase and boride.During the solution treatment,the irregularly shaped γ'phase and the boride are dissolved,but as the solution temperature increases,the β-NiAAl phase is precipitated in the alloy structure.During the aging process,the γ'phase and the boride are precipitated.It is re-precipitate from the matrix phase,and the new γ'phase and boride are finer and more dispersed.After 1080 ℃×4 h,AC+900 ℃×10 h,AC solution aging treatment,the alloy not only obtains fine dispersed γ'phase and boride reinforced structure,but also effectively inhibits the β-NiAl phase precipitation,which improves the mechanical properties of the alloy.
Ni3Allaser direct depositionboridemicrostructureheat treatment
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