Nanoscale steel-brass multilayer laminates made by cold rolling: microstructure

2019-11-09 03:40:17

strength steel thickness bilayer brass

责任者: Kavarana, F.H.;Ravichandran, K.S.;Sahay, S.S. 单位: Dept. of Metall. Eng., Utah Univ., Salt Lake City, UT, USA 来源出处: Scripta Materialia(Scr. Mater. (USA)),2000/05/10,42(10):947-54 摘要: Repeated cold rolling has been successfully used to produce high strength brass-steel nanoscale multilayers. A bilayer thickness as low as 15 nm and yield strength as high as 850 MPa was achieved. The existence of two different strengthening mechanisms in the cold-rolled and annealed brass-steel multilayers has been found. The critical bilayer thickness range was found to be between 39.2 and 78.4 nm, below which the strength levels did not change much, suggesting the Koehler strengthening mechanism. Above this critical thickness range, Hall-Petch type strengthening appears to be responsible for the strong increase of strength, with a decrease in bilayer spacing. The ductility in these multilayers decreased strongly with a decrease in bilayer thickness and there was the correspondence between the saturation of strength levels and that of the ductility level, at low bilayer thicknesses. Although the minimum ductility was consistent with the Koehler mechanism, the predicted and experimentally observed transitions differed significantly 关键词: brass;carbon steel;cold rolling;ductility;elongation;laminates;multilayers;nanostructured materials;yield strength;nanoscale steel-brass multilayer laminates;cold rolling;microstructure;bilayer thickness;yield strength;C steel;Koehler strengthening mechanism;critical thickness;Hall-Petch type strengthening;ductility;elongation