Decomposition Reaction of Metastable M2C Carbide in a Multi-Component Semi-High-Speed Steel

作者：Chen, Lei^*; Pei, Jianming; Li, Fei; Zhang, Yingjie; Wang, Mingjia; Ma, Xiaocong

来源：Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science, 2016, 47A(12): 5662-5669.

DOI：10.1007/s11661-016-3795-x

• ROLLING MILL ROLLS
• HEAT-TREATMENT
• CAST-IRON
• MICROSTRUCTURE
• SOLIDIFICATION
• TRANSFORMATION

The metastable M2C carbide in a multi-component semi-high-speed steel shows an in situ decomposition during heat treatment. M2C carbides transform themselves into an aggregate of three secondary carbides (M6C, MC, M7C3) at the M2C carbide/gamma-Fe matrix interface through the diffusion of various alloying elements. The content of the decomposition products decreases in the order of M6C, MC, and M7C3. The Fe-rich M6C is considered to be the eta (2)-type carbides of (Cr, V, Fe)(4)(Mo, W)(2)C, the MC consists primarily of V as the crystallized carbide does, and the M7C3 with 70 at. pct of Cr and Fe in total is formed only during heat treatment but not during solidification. At the heat treatment temperature of 1273 K (1000 A degrees C), a new approximate reaction equation of M2C + 0.052 gamma-Fe -> 0.687M(6)C + 0.044M(7)C(3) + 0.320MC is proposed based on the measurement of the composition of carbides; moreover, a modified prediction model of transformation ratio of M2C carbide is obtained according to the DSC experiments.

• 出版日期2016-12
• 单位燕山大学