pISSN : 1598-706X / eISSN : 2288-8381
한국주조공학회지 (21권1호 24-32)
Effects of Ti, Hf and Zr Alloying Elements on Mechanical Properties and Fracture Behaviors of Fe-30Al-5Cr Alloys
Fe-30Al-5Cr 합금의 기계적 성질 및 파면양상에 미치는 Ti, Hf 및 Zr의 첨가효과
Sung-Su Kim, Sung-Min Joo, Hyung-Gon Joo, Doh-Jae Lee, Dap-Chun Choi
Chonnam National University
Recently, iron aluminides based on Fe3Al and FeAl are ordered intermetallic alloys that offer good oxidation resistance, excellent sulfidation resistance, and potentially lower cost than many high- temperature structural materials. They have better strength, elasticity to weight ratio and high temperature strength, therefore, they can be cosidered as candidate heat resistance structural materials for automobiles, ships, airplanes and spaceships applications. The changes in the mechanical properties and fracture behavior were investigated for Fe-30at.%Al-5at.%Cr alloys when Ti, Hf and Zr were added respectively. For mechanical properties such as Rockwell hardness and yield strength at room temperature, those were decreased in the case of Fe- 30at.%Al-5at.%Cr alloy then increased in the case of 5at.% and 10at.% addition of Ti alone. However, Rockwell hardness and yield strength decreased again at 15%Ti then increased dramatically due to the precipitation hardening of the second phase on the specimen at 20%Ti. For fracture modes, cleavage fracture showed in the case of Fe-30at.%Al and Fe-30at.%Al- 5at.%Cr alloys. As the amount of Ti addition changed cleavage to transgranular fracture and to quasi-cleavage fracture at 20%Ti. When Hf, Zr and Hf+Zr were added respectively, transgranular, cleavage and quasi-cleavage fracture were coexisted.