Nanoparticles in magnesium alloys: Novel nanoscale phenomena to significant macroscale effects

Abstract

It is well known that ex-situ microparticles significantly strengthen magnesium alloys with consequent reduction in ductility. It is, however, not well known that ex-situ nanoparticles possess sufficiently smaller size (and significantly higher surface area) that enables intermetallic precipitation regulation at nanoscale in magnesium alloys. In this study, the intermetallic precipitation regulation ability of selected ex-situ nanoparticles (cabon nanotubes (CNTs) and Si3N4) in ZK60A magnesium alloy and associated tensile deformation mechanisms (both as nanoscale phenomena leading to the macroscale effect of significant increment in tensile ductility) are investigated. Also, the in-situ creation of nanoparticles in magnesium alloy and consequent simultaneous significant improvement of tensile strength and ductility is investigated. Here, metallic Zn was dissolved in molten ZK60A to predominantly form Mg-Zn nanorods in the alloy matrix. Finally, the significant increase in strength of AZ81 magnesium alloy due to CNT addition is discussed, this being attributed to the presence of hard segments consisting of nanograins due to nanoscale Al4C3 precipitation. Copyright © 2013 MS&T'13®.