The effect of strain path reversal on austenite grain subdivision and deformation induced ferrite transformation studied by hot torsion
The effects of large strain and strain path reversal on the deformation microstructure evolution in austenite below the recrystallisation temperature were studied by hot torsion using a non-transforming Fe-30wt％Ni model austenitic alloy. Results show that the high angle boundaries (HABs) can be generated by both microstructure mechanism through dislocation accumulation and texture mechanism via subgrain rotation. However, multiple strain path reversals lead to less well-developed HABs in the original grains compared to single reversal deformed to the same amount of total accumulative strain. This effect is attributed to the subgrain rotation mechanism being less effective at small strains. In comparison, the same hot torsion tests were conducted using a microalloyed steel at a temperature between Ae3 and Ar3-After single strain path reversal, substantial deformation-induced austenite-to-ferrite phase transformation was observed. Meanwhile, a test with multiple strain path reversals but with the same total strain produces much lower levels of strain-induced ferrite formation. This difference is correlated to the observations made in the Fe-30wt％Ni model alloy. It is believed that the different amount of strain-induced ferrite originated from the different levels of strain-induced HABs within the austenite which act as ferrite nucleation sites.
strain induced transformation ultra fine ferrite dislocation boundaries EBSD
SUN Lin MUSZKA Krzysztof WYNNE Bradley P PALMIERE Eric J
Institute for Microstructural and Mechanical Process Engineering,The University of Sheffield,Mappin Street, Sheffield S1 3JD,UK
国际会议
The 6th International Conference on High Strength Low Alloy Steels(第六届高强度低合金钢国际会议HSLA Steels2011)
北京
英文
331-334
2011-05-31（万方平台首次上网日期，不代表论文的发表时间）