Abstract
In this study,surface mechanical attrition treatment was employed to sucessfully produce a gradient nanostructured layer on WE43 magnesium alloy.X-ray diffraction,energy dispersive X-ray spectrometer,and high-resolution transmission electron microscope observations were mainly performed to uncover the microstructure evolution responsible for the refinement mechanisms.It reveals that the grain refine-ment process consists of three transition stages along the depth direction from the core matrix to the topmost surface layer,i.e.,dislocation cells and pile-ups,ultrafine subgrains,and randomly orientated nanograins with the grain size of～40 nm.Noticeably,the original Mg3RE second phase is also expe-rienced refinement and then re-dissolved into the α-Mg matrix phase,forming a supersaturated solid solution nanostructured α-Mg phase in the gradient refined layer.Due to the cooperative effects of grain refinement hardening,dislocation hardening,and supersaturated solid-solution hardening,the gradient nanostructured WE43 alloy contributes to the ultimate tensile strength of～435 MPa and ductility of～11.0％,showing an extraordinary strain hardening and mechanical properties among the reported se-vere plastic deformation-processed Mg alloys.This work provides a new strategy for the optimization of mechanical properties of Mg alloys via combining the gradient structure and supersaturated solid solu-tion.
基金项目
National Natural Science Founda-tion of China(51701171)
National Natural Science Founda-tion of China(51971187)
China Postdoctoral Science Foundation(2019M653599)
financial support from Partner State Key Laboratories in Hong Kong from the Innovation and Technology Commission ITC)of the ()
China and the PolyU Research Office(ProjectCode1-BBXA)
PolyU Research Committee under student account code RK25()
NETL
NSTL
维普
万方数据