Effective grain size refinement of an Fe-24Ni-0.3C metastable austenitic steel by a modified two-step cold rolling and annealing process utilizing the deformation-induced martensitic transformation and its reverse transformation
Effective grain size refinement of an Fe-24Ni-0.3C metastable austenitic steel by a modified two-step cold rolling and annealing process utilizing the deformation-induced martensitic transformation and its reverse transformation
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DOI：
10.1016/j.jmrt.2022.02.031
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发表时间：
2022-02
期刊：
影响因子：
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通讯作者：
W. Mao;Si-feng Gao;Yu Bai;Myeong-heom Park;A. Shibata;N. Tsuji
中科院分区：
文献类型：
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作者：
W. Mao;Si-feng Gao;Yu Bai;Myeong-heom Park;A. Shibata;N. Tsuji
具有超细晶粒（UFG）微观结构的亚稳奥氏体钢可以通过常规的冷轧和退火工艺通过利用冷轧期间的变形诱导马氏体转变和退火时其向奥氏体的逆转变来制造。然而，当奥氏体对变形诱导的马氏体相变具有高机械稳定性时，这种方法是不适用的，因为在冷轧期间没有足够量的马氏体形成。在本研究中，一个两步冷轧和退火工艺应用于Fe-24 Ni-0.3C亚稳奥氏体钢具有高的机械稳定性。在冷轧之前，施加重复的零度以下处理和反向退火处理。这样的处理显著降低了奥氏体的机械稳定性，并大大加速了在随后的冷轧过程中形变诱发马氏体的形成。结果表明，该工艺能有效地细化晶粒，获得了平均晶粒尺寸为0.5 μm的完全再结晶试样，该试样具有较高的强度和塑性。
Metastable austenitic steels having ultrafine grained (UFG) microstructures can be fabricated by conventional cold rolling and annealing processes by utilizing the deformation-induced martensitic transformation during cold rolling and its reverse transformation to austenite upon annealing. However, such processes are not applicable when the austenite has high mechanical stability against deformation-induced martensitic transformation, since there is no sufficient amount of martensite formed during cold rolling. In the present study, a two-step cold rolling and annealing process was applied to an Fe-24Ni-0.3C metastable austenitic steel having high mechanical stability. Prior to the cold rolling, a repetitive subzero treatment and reverse annealing treatment were applied. Such a treatment dramatically decreased the mechanical stability of the austenite and greatly accelerated the formation of deformation-induced martensite during the following cold rolling processes. As a result, the grain refinement was significantly promoted, and a fully recrystallized specimen with a mean austenite grain size of 0.5 μm was successfully fabricated, which exhibited both high strength and high ductility.