1. Realizing ultra-fine grains and ultra-high strength in conventionally extruded Mg-Ca-Al-Zn-Mn alloys: The multiple roles of nano-precipitations.
- Author
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Li, Man, Xie, Dongsheng, Li, Jingren, Xie, Hongbo, Huang, Qiuyan, Pan, Hucheng, and Qin, Gaowu
- Subjects
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MAGNESIUM alloys , *ALLOYS , *PRECIPITATION hardening , *TENSILE strength , *HEAT treatment , *CRYSTAL grain boundaries , *EXTRUSION process - Abstract
An ultra-high strength and low-cost magnesium wrought alloy, Mg-1Ca-1Al-0.3Zn-0.4Mn (wt%), has been fabricated by conventional extrusion, with yield strength of ~435 MPa, the ultimate tensile strength of ~449 MPa and the elongation of ~4.2%. Mono-dispersive nano-precipitations, e.g., the Al 2 Ca phase and AlMn phase, have been induced during extrusion, which can effectively pin pyramidal dislocation motions in grain interiors and thus provide substantial nucleation sites for dynamic recrystallization in present Ca-containing Mg alloys. Simultaneously, these fine-precipitates distributing at the new grain boundaries can prevent their growths, which thus guarantee the ultra-fine grains formation (300–500 nm). After heat treatment, a higher number density of nano Al 2 Ca and AlMn phases can be further precipitated, which results in the alloy still maintaining the ultra-high strength of ~444 MPa. The multiple roles of the same nano-precipitations in both promoting the ultrafine grains formation and affording precipitation hardening have been clarified in present Mg wrought alloy. • Ultra-high strength of ~449 MPa was achieved in the low-cost Mg-1Ca-1Al-0.3Zn-0.4Mn (wt%) wrought alloy. • Ultra-fine grain size (300–500 nm) was achieved due to ther fine-precipitates distributing at the new grain boundaries. • A higher number density of nano-precipitations could afford extra precipitation hardening effect after heat treatment. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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