The structural transitions of Ti₃AlC₂ induced by ion irradiation

详细信息    查看全文

• 作者：Tengfei Yang ; Chenxu Wang ; Caitlin A. Taylor ; Xuejun Huang ; Qing Huang ; Fangzhi Li ; Lu Shen ; Xiaobin Zhou ; Jianming Xue ; Sha Yan ; Yugang Wang
• 关键词：Irradiation effect ; Order-to-disorder phase transformations ; Electron diffraction pattern ; Ceramics
• 刊名：Acta Materialia
• 出版年：15 February, 2014
• 年：2014
• 卷：65
• 期：Complete
• 页码：351-359
• 全文大小：1930 K

文摘

The structural transitions of Ti₃AlC₂ induced by ion irradiation were investigated over a wide fluence range by transmission electron microscopy. No amorphization occurs even at the highest dose of 31 dpa, indicating a great tolerance to irradiation-induced amorphization. Dynamic electron diffraction simulations and high-resolution observations indicate that the nanolamellar structure of Ti₃AlC₂ is readily destroyed through the formation of antisite defects and a phase transformation from 伪-Ti₃AlC₂ to 尾-Ti₃AlC₂ occurs at 2.61 dpa. A great number of stacking faults in basal planes are formed with increasing fluence, leading to the formation of nano Ti₃AlC₂ grains with different stacking sequences at 10.45 dpa. Serious structural damage and polygonization are observed at the highest dose of 31 dpa. Due to the similar structural transition process with some complex oxides (pyrochlore and murataite), it is assumed that the great irradiation tolerance of Ti₃AlC₂ results from the low formation energy of antisite defects. These findings first clarify the structural transition mechanism of Ti₃AlC₂ under ion irradiation and its relationship with irradiation tolerance, which is of vital importance in understanding the irradiation response of MAX phases and provides a clue in searching for materials with higher irradiation tolerance from MAX phases.