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Vol.41, No.12, 813 ~ 821, 2003
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| Title |
| Effects of Ternary Elements on Phase Transformation and Microstructure of NiAl/Ni3Al Two-Phase Alloys |
| 송성훈 Song Seong Hun , 김수현 Kim Su Hyeon , 오명훈 O Myeong Hun , 위당문 Wi Dang Mun |
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| Abstract |
| The microstructural evolution of b-NiAl/γ` -Ni3Al two-phase (Ni_(66)Al_(34))_(100-x)X_(X)(X=Ti, Si, Nb) alloys during various heat treatment (quenching and aging) were systematically studied. It was found that the microstructural features of the two-phase NiAl/Ni₃Al alloys could be divided into three types : lamellar, mesh and Widmansttten microstructures. The reason why those three types of microstructure were formed could be explained by the change of austenite start temperature(As temperature) depending on the ternary elements. In case of As>250℃, the lamellar microstructure was formed by following phase transformation: Martensite→Ni5Al3→β+γ` . In this case, the NiAl martensite was quickly transformed into the Ni5Al3 phase at 250℃ by a re-ordering reaction. In case of 20℃
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| Key Words |
| NiA1/Ni3Al two-phase alloys, Ternary element, Martensitic transformation, Ni3Al3, Microstructural control |
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