Release Time:2019-03-11  Hits:

Indexed by: Journal Article

Date of Publication: 2018-04-18

Journal: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

Included Journals: EI、SCIE

Volume: 273

Page Number: 118-125

ISSN: 0921-5093

Key Words: Mg-Zn-RE-Zr-Ca; Sr; Microstructure; Fluidity; Mechanical properties

Abstract: Microstructure, fluidity and mechanical properties of Mg-4.2Zn-1.7RE-0.8Zr-0.2Ca (wt%) alloy with minor Sr contents have been investigated. All the alloys exhibited the homogeneous microstructure with equiaxed alpha-Mg matrix and eutectic compounds distributing along grain boundaries. The as-cast alloys are mainly composed of alpha-Mg phase, Mg51Zn20 phase and T-phase. The fluidity of the Sr-containing Mg alloys was examined by means of the three concentric spirals mould. It was found that the fluidity of Mg-4.2Zn-1.7RE-0.8Zr-0.2Ca-0.2 Sr alloy was effectively increased by 122.8% as compared to the quaternary alloy. This could be attributed to grain refinement as well as the reductions of oxides and melt viscosity. The Mg-4.2Zn-1.7RE-0.8Zr-0.2Ca-0.2 Sr alloy exhibits the optimum tensile properties with ultimate tensile strength, yield strength and elongation of 144.1 MPa, 114.4 MPa and 4.9%, respectively, which is ascribed to refinement strengthening and dislocation pinning effect of T-phase. Furthermore, the fracture characteristic of Sr-containing alloys is mainly quasi-cleavage.