Unusual relationship between impact toughness and grain size in a high-manganese steel

Pan Xie, Shucheng Shen, Cuilan Wu, Jiehua LI, Jianghua Chen

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

3 Zitate (Scopus)


The high-manganese steels are important structural materials, owing to their excellent toughness at low temperatures. However, the microstructural causes for their unusual properties have not adequately been understood thus far. Here, we report a reversal relationship between impact toughness and grain size in a high-manganese steel and its unrevealed microscopic mechanisms, which result in an excellent low-temperature toughness of the steel. Our investigations show that with increasing grain size the impact toughness of the steel can be improved drastically, especially at low-temperatures. Advanced electron microscopy characterization reveals that the enhanced impact toughness of the coarse-grained steel is attributed to the twinning induced plasticity and transformation induced plasticity effects, which produce large quantities of deformation twins, ε hcp-martensite and α′ bcc-martensite. Inversely, in the fine-grained steels, the formation of deformation twins and martensite is significantly inhibited, leading to the decrease of impact toughness. Microstructural characterizations also indicate that ε hcp-martensite becomes more stable than α′ bcc-martensite with decreasing temperature, resulting in characteristic microstructures in the coarse-grained samples after impact deformation at liquid nitrogen temperature. In the coarse-grained samples under impact deformation at -80 °C, ε hcp-martensite transformation, α′ bcc-martensite transformation and deformation twinning all occur simultaneously, which greatly improves the toughness of the steel.

Seiten (von - bis)122-132
Ausgabenummer30 October
PublikationsstatusElektronische Veröffentlichung vor Drucklegung. - 13 Apr. 2021

Bibliographische Notiz

Funding Information:
This work is supported by the National Natural Science Foundation of China [Grant Nos. 51801060 ; 51831004 ; 11427806 ; 51671082 ]; the China Postdoctoral Science Foundation (grant number 2019M652756 ); the National Key Research and Development Program of China (grant number 2016YFB0300801 ), and the China Scholarship Council (grant number 201606130008 ). Jiehua Li gratefully acknowledges the financial support from Austrain Science Fund (FWF) (grant number P 32378-N37 ) and BMBWF (grant number KR 06/2020 ).

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