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pISSN : 1598-706X / eISSN : 2288-8381


(논문)연구논문

한국주조공학회지 (24권6호 356-365)

Microstructures and Mechnical Properties of Ni-Al-Fe Ternary Alloys

Ni-Al-Fe 3 원계합금의 미세조직 및 기계적 특성

Dap-Chun Choi, Dae-Sung Bae

Chonnam National Univ.

Abstract

Mechanical properties and microstructures of the Ni-Al-Fe and Ni-Al-Fe-(B, Zr) alloys which containing 10~3oat.%Fe,0.lat.%B and/or 0.lat.%Zr have been investigated. The experimental results showed that the microstructures of Ni25Al were changed from a single phase V to dual phase }/and [3 by addition of 27at.%Fe. Ni45Al, however, kept the single [3 phase even though Fe was added upto 3oat.%. The hardness of Ni25Al were increased from HRB 70 to I-[RC 39 by addition of 27at.%Fe. In the case of Ni45Al which have HRC 37, the hardness was decreased by loat.%Fe addition, but increased with 3oat.%Fe. The yield strength and ultimate compressive strength in the compressive test have showed a similar trend with the hardness change. The strain to fracture was 14% at maximum and achieved in Ni25Al-27at.%Fe and Ni25A1-27at.%Fe-0. lat.%B alloys. The Ni45Al showed a relatively low strain to fracture as 4%. The impact absorption energy of Ni25Al increased from 0.74 kg-m to 1.81 kg-m by addition of 27at.%Fe. In case of Ni45Al, the addition of loat.%Fe and 1oat.%Fe with small amounts of B and Zr did not change significantly the impact absorption energy of 0.60 kg-m, whereas the addition of 3oat.%Fe with small amounts of B and Zr increased it slightly. In fracture tests, both of two basic materials showed the same intergranular fracture but by adding Fe it changed to the cleavage fracture mode or co-existing of cleavage and intergranular fractures.

Keywords

Ni-Al-Fe ternary alloys, Microstructures, Mechanical properties, Intergranular fracture, Cleavage fracture.