Phase Transformations of Fe-8Al-30Mn-1C-3Cu Alloy

• Main Authors: Yao-Ru Peng, 彭耀儒
• Other Authors: Chih-Yeh Chao
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/21427954411594080716

碩士 === 國立屏東科技大學 === 機械工程系所 === 97 === The microstructure of the as-quenched specimen was a single austenite phase with annealing twins. The lattice parameter of austenite phase is a=0.367nm. Being aged at 450℃ for a various time, the fine κ'-phase carbides were found within the matrix coherently. Increasing the aging temperature to 550~650℃, the γ＋κ' phase transition occurred within the matrix. However, prolonged aging time more than 144 hours, some coarse κ-phase carbides were precipitated on the grain boundaries, the lattice parameter of the carbides being a=0.379nm. It reveals that the coarse κ carbides grew into the adjacent γ grains through a γ → γ + κ reaction. The mixture of (γ+κ carbide) had a lamellar structure. Based on the SEM-EDS examinations, the κ-phase carbides were possessed the higher copper, indicating that the copper will play an important role on the phase transition sequences of grain boundary. In addition, the Cu-richer κ-phase carbides would posses higher lattice parameter in the range between 0.379~0.382nm. The lattice parameter of the κ'-phase carbides being a=0.379nm.