Aging hardening response and β-Mn transformation behavior of high carbon high manganese austenitic low-density Fe-30Mn-10Al-2C steel

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 703; pp. 167 - 172
• Main Authors: Chen, X.P., Xu, Y.P., Ren, P., Li, W.J., Cao, W.Q., Liu, Q.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 04-08-2017
• Subjects: Aging; Hardening response; Low-density steel; Transformation; β-Mn; Aging; β-Mn; Transformation; Low-density steel; Hardening response
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2017.07.055

Aging treatments under three temperatures were performed to investigate the aging hardening response of high carbon high manganese austenitic Fe-30Mn-10Al-2C steel. The dramatic differences in hardness and microstructure were observed after aging under different temperatures. The aging treated at 500℃ had a typical aging hardness curve and the hardening response originated from the precipitation of κ-carbide, which plays an important role in performance improvement. When aging was conducted at 700℃, there was no significant change in hardness because a balance between aging hardening and high-temperature softening was built. On the contrary, the aging under 600℃ exhibited novel continuous increase in hardness and dramatic secondary hardening due to the formation of β-Mn which had an intrinsic high hardness. In addition, the β-Mn was also found after aging for long time under other temperatures. Unfortunately, the formation of β-Mn distributed along γ grain boundaries led to serious brittle fracture. For further investigation and application, the β-Mn transformation behavior was discussed based on the diffusion and redistribution of elements. Considering the dramatic difference in the formation kinetics of β-Mn depending on aging temperature, the diagram of β-Mn transformation was achieved to obtain optimized aging conditions.