title: Microalloying ultrafine grained Al alloys with enhanced ductility.
abstract: Bulk ultrafine grained (UFG)/nanocrystal metals possess exceptional strength but normally poor ductility and thermal stability, which hinder their practical applications especially in high-temperature environments. Through microalloying strategy that enables the control of grains and precipitations in nanostructured regime, here we design and successfully produce a highly microstructure-stable UFG Al-Cu-Sc alloy with ~275% increment in ductility and simultaneously ~50% enhancement in yield strength compared with its Sc-free counterpart. Although the precipitations in UFG alloys are usually preferentially occurred at grain boundaries even at room temperature, minor Sc addition into the UFG Al-Cu alloys is found to effectively stabilize the as-processed microstructure, strongly suppress the θ-Al2Cu phase precipitation at grain boundary, and remarkably promote the θ'-Al2Cu nanoparticles dispersed in the grain interior in artificial aging. A similar microalloying strategy is expected to be equally effective for other UFG heat-treatable alloys.
authors.affiliation: State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, PR China.
authors.forename: L
authors.initials: L
authors.lastname: Jiang
authors.affiliation: State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, PR China.
authors.forename: J K
authors.initials: JK
authors.lastname: Li
authors.affiliation: State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, PR China.
authors.forename: P M
authors.initials: PM
authors.lastname: Cheng
authors.affiliation: State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, PR China.
authors.forename: G
authors.initials: G
authors.lastname: Liu
authors.affiliation: School of Materials Science and Engineering, Xi'an University of Technology, Xi'an, 710048, PR China.
authors.forename: R H
authors.initials: RH
authors.lastname: Wang
authors.affiliation: State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, PR China.
authors.forename: B A
authors.initials: BA
authors.lastname: Chen
authors.affiliation: State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, PR China.
authors.forename: J Y
authors.initials: JY
authors.lastname: Zhang
authors.affiliation: State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, PR China.
authors.forename: J
authors.initials: J
authors.lastname: Sun
authors.affiliation: Central Iron and Steel Research Institute, Beijing, 100081, PR China.
authors.forename: M X
authors.initials: MX
authors.lastname: Yang
authors.affiliation: Central Iron and Steel Research Institute, Beijing, 100081, PR China.
authors.forename: G
authors.initials: G
authors.lastname: Yang